how to insert keyboard func in opengl prog

OpenGL OpenGL: Basic Coding
1

Hi
How to add keyboard interaction func to specific part in my program
i)I’m using 1 & 2 key to select stack and queue respectively(its working fine),but the thing is I wanted to add some key(say 5,6) to push,pop in stack and key 7,8 to insert & remove in queue
ii)think that i’ve made some operation on stack(say stack full) by using m/M key we are able to come back to main menu once again if i go to stack its still stack full so,tell me how to reset the operation (ie stack empty)
iii)firstly if i go to stack then do some operation on stack and if i come to menu and then once again if i enter into queue its showing some error

plz help me out

#include<GL/glut.h>
#include<GL/glu.h>
#include<string.h>
#include<stdio.h>
GLfloat v[][8][3]={{{-1.5,-1.5,-1.0},{-1.3,-1.5,-1.0},{-1.3,-1.3,-1.0},{-1.5,-1.3,-1.0},{-1.6,-1.6,1.0},{-1.4,-1.6,1.0},{-1.4,-1.4,1.0},{-1.6,-1.4,1.0}} , {{-1.3,-1.5,-1.0},{-1.1,-1.5,-1.0},{-1.1,-1.3,-1.0},{-1.3,-1.3,-1.0},{-1.4,-1.6,1.0},{-1.2,-1.6,1.0},{-1.2,-1.4,1.0},{-1.4,-1.4,1.0}} , {{-1.1,-1.5,-1.0},{-0.9,-1.5,-1.0},{-0.9,-1.3,-1.0},{-1.1,-1.3,-1.0},{-1.2,-1.6,1.0},{-1.0,-1.6,1.0},{-1.0,-1.4,1.0},{-1.2,-1.4,1.0}} , {{-1.5,-1.3,-1.0},{-1.3,-1.3,-1.0},{-1.3,-1.1,-1.0},{-1.5,-1.1,-1.0},{-1.6,-1.4,1.0},{-1.4,-1.4,1.0},{-1.4,-1.2,1.0},{-1.6,-1.2,1.0}} , {{-1.3,-1.3,-1.0},{-1.1,-1.3,-1.0},{-1.1,-1.1,-1.0},{-1.3,-1.1,-1.0},{-1.4,-1.4,1.0},{-1.2,-1.4,1.0},{-1.2,-1.2,1.0},{-1.4,-1.2,1.0}} , {{-1.1,-1.3,-1.0},{-0.9,-1.3,-1.0},{-0.9,-1.1,-1.0},{-1.1,-1.1,-1.0},{-1.2,-1.4,1.0},{-1.0,-1.4,1.0},{-1.0,-1.2,1.0},{-1.2,-1.2,1.0}} , {{-1.5,-1.1,-1.0},{-1.3,-1.1,-1.0},{-1.3,-0.9,-1.0},{-1.5,-0.9,-1.0},{-1.6,-1.2,1.0},{-1.4,-1.2,1.0},{-1.4,-1.0,1.0},{-1.6,-1.0,1.0}} , {{-1.3,-1.1,-1.0},{-1.1,-1.1,-1.0},{-1.1,-0.9,-1.0},{-1.3,-0.9,-1.0},{-1.4,-1.2,1.0},{-1.2,-1.2,1.0},{-1.2,-1.0,1.0},{-1.4,-1.0,1.0}} , {{-1.1,-1.1,-1.0},{-0.9,-1.1,-1.0},{-0.9,-0.9,-1.0},{-1.1,-0.9,-1.0},{-1.2,-1.2,1.0},{-1.0,-1.2,1.0},{-1.0,-1.0,1.0},{-1.2,-1.0,1.0}}};
GLfloat colors[][3]={{0.0,0.0,0.0},{1.0,0.0,0.0},{1.0,1.0,0.0},{0.0,1.0,0.0},{1.0,0.0,1.0},{0.0,1.0,1.0}};
GLfloat st[][3]={{1.8,-1.5,-1.0},{2.0,-1.5,-1.0},{2.0,0.9,-1.0},{1.8,0.9,-1.0},{1.7,-1.6,1.0},{1.9,-1.6,1.0},{1.9,0.8,1.0},{1.7,0.8,1.0}};
GLint i,h,m,k,n=5;
GLfloat tempv[8][3];
GLint tos=-1,maxsize=5,g=-1,f=0,ch,fr=-1,r=-1;
GLfloat tempst=-1.5,sttos=-1.9;
GLfloat stcube[9][8][3];
GLint pu=0,po=0,in=0,l,o,rear,node=0;
GLfloat tx=0.0,ty=1.0,stfr=-1.5,str=-1.4;
int out=0;
void polygon(int a,int b,int c,int d,int i)
{
 glBegin(GL_POLYGON);
 glColor3fv(colors[a]);
 glVertex3fv(v[i][a]);
 glColor3fv(colors[b]);
 glVertex3fv(v[i][b]);
 glColor3fv(colors[c]);
 glVertex3fv(v[i][c]);
 glColor3fv(colors[d]);
 glVertex3fv(v[i][d]);
 glFlush();                      // force execution of GL commands in finite time
 glEnd();
}
void colorcube()
{
 polygon(0,3,2,1,i);
 polygon(2,3,7,6,i);
 polygon(0,4,7,3,i);
 polygon(1,2,6,5,i);
 polygon(4,5,6,7,i);
 polygon(0,1,5,4,i);
}
void stack(int a,int b,int c,int d)
{

 glBegin(GL_POLYGON);
 glColor3f(1.0,1.0,1.0);
 glVertex3fv(st[a]);
 glColor3fv(colors[b]);
 glVertex3fv(st[b]);
 glColor3f(1.0,1.0,1.0);
 glVertex3fv(st[c]);
 glColor3fv(colors[d]);
 glVertex3fv(st[d]);
 glFlush();
 glEnd();
}
void stackcube()
{
 stack(0,3,2,1);
 stack(2,3,7,6);
 stack(0,4,7,3);
 stack(1,2,6,5);
 stack(4,5,6,7);
 stack(0,1,5,4);
}
void resultpolygon(int a,int b,int c,int d)
{
 glBegin(GL_POLYGON);
 glColor3fv(colors[a]);
 glVertex3fv(tempv[a]);
 glColor3fv(colors[b]);
 glVertex3fv(tempv[b]);
 glColor3fv(colors[c]);
 glVertex3fv(tempv[c]);
 glColor3fv(colors[d]);
 glVertex3fv(tempv[d]);
 glFlush();
 glEnd();
}
void resultcolorcube()
{
 resultpolygon(0,3,2,1);
 resultpolygon(2,3,7,6);
 resultpolygon(0,4,7,3);
 resultpolygon(1,2,6,5);
 resultpolygon(4,5,6,7);
 resultpolygon(0,1,5,4);
}
void stackpolygon(int a,int b,int c,int d,int f)
{

 glBegin(GL_POLYGON);
 glColor3fv(colors[a]);
 glVertex3fv(stcube[f][a]);
 glColor3fv(colors[b]);
 glVertex3fv(stcube[f][b]);
 glColor3fv(colors[c]);
 glVertex3fv(stcube[f][c]);
 glColor3fv(colors[d]);
 glVertex3fv(stcube[f][d]);
 glFlush();
 glEnd();
}
void stackcolorcube()
{
 stackpolygon(0,3,2,1,f);
 stackpolygon(2,3,7,6,f);
 stackpolygon(0,4,7,3,f);
 stackpolygon(1,2,6,5,f);
 stackpolygon(4,5,6,7,f);
 stackpolygon(0,1,5,4,f);
}
void init()
{
	glClearColor(0.1,0.1,0.1,1.0);
	gluOrtho2D(0.0,599.0,0.0,599.0);
}
void text(char str[])
{
 int i;
 for(i=0;i<strlen(str);i++)
 {
	 glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,str[i]);
 }
}
void form2()
{
 glColor3f(0.8,0.2,0.7);
 glRasterPos3f(-1.6,0.85,-1.0);
 text("1. Press 1 to goto Stack");
 glRasterPos3f(-1.8,1.45,-1.0);
 text("NAVIGATION OPTIONS");
 glRasterPos3f(-1.6,0.55,-1.0);
 text("2. Press 2 to goto Queue");
 glRasterPos3f(-1.6,-0.05,-1.0);
 text("4. Press 4 to exit");
 glFlush();
 glEnd();
}
void display()
{
 glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
 glLoadIdentity();
if(out==0)
  form2();

 else
 {
  if(ch==1)
  {
  	glColor3f(0.8,0.2,0.7);
  	if(sttos<-1.5)    //position of the tos near storage block
  	 	glRasterPos3f(1.45,sttos+0.4,1.0);
   	 else
   		glRasterPos3f(1.45,sttos,1.0);
  		text("tos>>");
 	 glFlush();
 	 for(i=0;i<=n;i++)
 	    colorcube();   //stack small block
	    stackcube();   //stack storage block
	    resultcolorcube();  //small block movement ray into storage block
 	for(f=0;f<=tos;f++)
  		stackcolorcube();   //display of the small block in stotage block
 glColor3f(0.8,0.2,0.7);
  glRasterPos3f(1.7,-1.8,1.0);
  text("Stack");
  glFlush();
  if(tos==-1)
  {
   glColor3f(0.8,0.2,0.7);
   glRasterPos3f(-0.5,0.0,-1.0);
   text("Stack Empty");
   glFlush();
  }
  if(tos>=maxsize)
  {
   glColor3f(0.8,0.2,0.7);
   glRasterPos3f(-0.5,0.0,-1.0);
   text("Stack Full");
   glFlush();
  }
}
 else if(ch==2)
 {
  glColor3f(1.0,0.0,0.0);
  glRasterPos3f(1.38,stfr,1.0);
  text("front>>");
  glFlush();

  glColor3f(1.0,0.0,0.0);
  glRasterPos3f(1.4,str,1.0);
  text("rear>>");
  glFlush();

  glColor3f(0.8,0.2,0.7);
  glRasterPos3f(2.1,-0.2,1.0);
  glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,'Q');
  glRasterPos3f(2.1,-0.35,1.0);
  glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,'u');
  glRasterPos3f(2.1,-0.5,1.0);
  glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,'e');
  glRasterPos3f(2.1,-0.65,1.0);
  glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,'u');
  glRasterPos3f(2.1,-0.8,1.0);
  glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,'e');
  glFlush();
  for(i=0;i<=n;i++)
   colorcube();
  stackcube();
  resultcolorcube();
 for(f=fr;f<=r;f++)
  stackcolorcube();
  if(r==-1)
  {
   glColor3f(0.8,0.2,0.7);
   glRasterPos3f(-0.5,0.0,-1.0);
   text("Queue Empty");
   glFlush();
  }
  if(r>=maxsize)
  {
   glColor3f(0.8,0.2,0.7);
   glRasterPos3f(-0.5,0.0,-1.0);
   text("Queue Full");
   glFlush();
  }
 }

 glColor3f(0.5,0.6,0.8);
 glRasterPos3f(-0.5,1.45,-1.0);
 text("Press m/M to goto Main Menu");
 glFlush();
 }
 if(ch==4)
	 exit(0);
 glutSwapBuffers();

}
void myreshape(int w,int h)
{
 glViewport(0,0,w,h);
 glMatrixMode(GL_PROJECTION);
 glLoadIdentity();
 if(w<=h)
  glOrtho(-2.0,2.0,-2.0*(GLfloat)h/(GLfloat)w,2.0*(GLfloat)h/(GLfloat)w,-10.0,10.0);
 else
  glOrtho(-2.0*(GLfloat)w/(GLfloat)h,2.0*(GLfloat)w/(GLfloat)h,-2.0,2.0,-10.0,10.0);
 glMatrixMode(GL_MODELVIEW);
}
void push()
{
 if(tos<maxsize)
 {
  for(h=0;h<8;h++)
   for(m=0;m<3;m++)
    tempv[h][m]=v[i][h][m];
  n--;
  display();
  while(tempv[0][1]<=1.0)
  {
   for(k=0;k<8;k++)
    tempv[k][1]=tempv[k][1]+0.1;
   display();
  }
 while(tempv[0][0]<=st[0][0])
 {
  for(k=0;k<8;k++)
   tempv[k][0]=tempv[k][0]+0.1;
  display();
  }
 while(tempv[0][1]>tempst)
 {
  for(k=0;k<8;k++)
   tempv[k][1]=tempv[k][1]-0.1;
  display();
 }
  tos++;
  for(h=0;h<8;h++)
   for(m=0;m<3;m++)
    stcube[tos][h][m]=tempv[h][m];
  tempst+=0.4;
  sttos+=0.4;
  display();
 }
 else
 {
  display();
 }
}
void pop()
{
 if(tos>=0)
 {
  for(h=0;h<8;h++)
   for(m=0;m<3;m++)
    tempv[h][m]=stcube[tos][h][m];
  tos--;
  display();
  while(tempv[0][1]<=1.0)
  {
   for(k=0;k<8;k++)
    tempv[k][1]=tempv[k][1]+0.1;
   display();
  }
  while(tempv[0][0]>v[i][0][0])
  {
   for(k=0;k<8;k++)
    tempv[k][0]=tempv[k][0]-0.1;
   display();
  }
  while(tempv[0][1]>v[i][0][1])
  {
   for(k=0;k<8;k++)
    tempv[k][1]=tempv[k][1]-0.1;
   display();
  }
  tempst-=0.4;
  display();
  sttos-=0.4;
  n++;
  display();
 }
 else
 {
  display();
 }
}
void stack_menu(int id)
{
 switch(id)
 {
  case 1:i--;push();break;
  case 2:pop();break;
 case 4:exit(0);
	  break;
 }
}
void mymenu()
{
 glutCreateMenu(stack_menu);
 glutAddMenuEntry("Push",1);
 glutAddMenuEntry("Pop",2);
 glutAddMenuEntry("Exit",4);
 glutAttachMenu(GLUT_RIGHT_BUTTON);
}
void insert()
{
 if(r>=maxsize)
  display();
 else
 {
  for(h=0;h<8;h++)
   for(m=0;m<3;m++)
    tempv[h][m]=v[i][h][m];
  n--;
  display();
  while(tempv[0][1]<=1.0)
  {
   for(k=0;k<8;k++)
    tempv[k][1]=tempv[k][1]+0.1;
   display();
  }
 while(tempv[0][0]<=st[0][0])
 {
  for(k=0;k<8;k++)
   tempv[k][0]=tempv[k][0]+0.1;
  display();
 }
 while(tempv[0][1]>tempst)
 {
  for(k=0;k<8;k++)
   tempv[k][1]=tempv[k][1]-0.1;
  display();
 }
  tempst+=0.4;
  r++;
  for(h=0;h<8;h++)
   for(m=0;m<3;m++)
    stcube[r][h][m]=tempv[h][m];
  display();
  str+=0.4;
  if(r==maxsize)
   str-=0.4;
  if(fr==-1)
	  fr=0;
 }
}
void remove()
{
 if(fr==-1)
  display();
 else if(fr<=r)
 {
  for(h=0;h<8;h++)
   for(m=0;m<3;m++)
	tempv[h][m]=stcube[fr][h][m];
  fr++;
  display();
  stfr+=0.4;
  if(fr>r)
   stfr-=0.4;
  while(tempv[0][1]>-1.8)
  {
   for(k=0;k<8;k++)
	tempv[k][1]=tempv[k][1]-0.1;
   display();
  }
  while(tempv[0][0]>0.0)
  {
   for(k=0;k<8;k++)
	tempv[k][0]=tempv[k][0]-0.1;
   display();
  }
  while(tempv[0][1]<1.0)
  {
   for(k=0;k<8;k++)
	tempv[k][1]=tempv[k][1]+0.1;
   display();
  }
  while(tempv[0][0]>v[i][0][0])
  {
   for(k=0;k<8;k++)
	tempv[k][0]=tempv[k][0]-0.1;
   display();
  }
  while(tempv[0][1]>v[i][0][1])
  {
   for(k=0;k<8;k++)
	tempv[k][1]=tempv[k][1]-0.1;
   display();
  }
  if(fr>r)
  {
   fr=-1;
   r=-1;
   tempst=-1.5;
   str=-1.4;
   stfr=-1.5;
  }
  n++;
  display();
 }
}
void queuemenu(int id)
{
 switch(id)
 {
  case 1:i--;insert();break;
  case 2:remove();break;
  case 4:break;exit(0);
 }
}
void myqmenu()
{
 glutCreateMenu(queuemenu);
 glutAddMenuEntry("Insert",1);
 glutAddMenuEntry("Remove",2);
 glutAddMenuEntry("Exit",4);
 glutAttachMenu(GLUT_RIGHT_BUTTON);
}
void keyboard(unsigned char key,int x,int y)
{
 if(key=='1')
 {
  out=3;
  ch=1;
  n=5;
  i=0;
  tos=-1;
  sttos=-1.9;
  tempst=-1.5;
  mymenu();
  display();
 }
 if(key=='2')
 {
  out=3;
  ch=2;
  n=5;
  i=0;
  r=fr=-1;
  stfr=-1.5;
  str=-1.4;
  tempst=-1.5;
  myqmenu();
  display();
 }
 if(key=='4')
 {
  exit(0);
 }
 if(key=='m'||key=='M')
 {
  out=0;
  display();
 }
}
int main(int argc,char **argv)
{
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB|GLUT_DEPTH);
  glutInitWindowSize(600,600);
  glutCreateWindow("colorcube");
  init();
  glutKeyboardFunc(keyboard);
  glutReshapeFunc(myreshape);
  glutDisplayFunc(display);
  glutMainLoop();
 return 0;
}
2

Firstly, the code formatting is just plain awful. Here is the readable version:

#include<GL/glut.h>
#include<GL/glu.h>
#include<string.h>
#include<stdio.h>



GLfloat v[][8][3]=
    {{{-1.5,-1.5,-1.0}, {-1.3,-1.5,-1.0}, {-1.3,-1.3,-1.0}, {-1.5,-1.3,-1.0},
      {-1.6,-1.6, 1.0}, {-1.4,-1.6, 1.0}, {-1.4,-1.4, 1.0}, {-1.6,-1.4, 1.0}},
     {{-1.3,-1.5,-1.0}, {-1.1,-1.5,-1.0}, {-1.1,-1.3,-1.0}, {-1.3,-1.3,-1.0},
      {-1.4,-1.6, 1.0}, {-1.2,-1.6, 1.0}, {-1.2,-1.4, 1.0}, {-1.4,-1.4, 1.0}},
     {{-1.1,-1.5,-1.0}, {-0.9,-1.5,-1.0}, {-0.9,-1.3,-1.0}, {-1.1,-1.3,-1.0},
      {-1.2,-1.6, 1.0}, {-1.0,-1.6, 1.0}, {-1.0,-1.4, 1.0}, {-1.2,-1.4, 1.0}},
     {{-1.5,-1.3,-1.0}, {-1.3,-1.3,-1.0}, {-1.3,-1.1,-1.0}, {-1.5,-1.1,-1.0},
      {-1.6,-1.4, 1.0}, {-1.4,-1.4, 1.0}, {-1.4,-1.2, 1.0}, {-1.6,-1.2, 1.0}},
     {{-1.3,-1.3,-1.0}, {-1.1,-1.3,-1.0}, {-1.1,-1.1,-1.0}, {-1.3,-1.1,-1.0},
      {-1.4,-1.4, 1.0}, {-1.2,-1.4, 1.0}, {-1.2,-1.2, 1.0}, {-1.4,-1.2, 1.0}},
     {{-1.1,-1.3,-1.0}, {-0.9,-1.3,-1.0}, {-0.9,-1.1,-1.0}, {-1.1,-1.1,-1.0},
      {-1.2,-1.4, 1.0}, {-1.0,-1.4, 1.0}, {-1.0,-1.2, 1.0}, {-1.2,-1.2, 1.0}},
     {{-1.5,-1.1,-1.0}, {-1.3,-1.1,-1.0}, {-1.3,-0.9,-1.0}, {-1.5,-0.9,-1.0},
      {-1.6,-1.2, 1.0}, {-1.4,-1.2, 1.0}, {-1.4,-1.0, 1.0}, {-1.6,-1.0, 1.0}},
     {{-1.3,-1.1,-1.0}, {-1.1,-1.1,-1.0}, {-1.1,-0.9,-1.0}, {-1.3,-0.9,-1.0},
      {-1.4,-1.2, 1.0}, {-1.2,-1.2, 1.0}, {-1.2,-1.0, 1.0}, {-1.4,-1.0, 1.0}},
     {{-1.1,-1.1,-1.0}, {-0.9,-1.1,-1.0}, {-0.9,-0.9,-1.0}, {-1.1,-0.9,-1.0},
      {-1.2,-1.2, 1.0}, {-1.0,-1.2, 1.0}, {-1.0,-1.0, 1.0}, {-1.2,-1.0, 1.0}}};

GLfloat colors[][3]=
    {{0.0,0.0,0.0}, {1.0,0.0,0.0}, {1.0,1.0,0.0},
     {0.0,1.0,0.0}, {1.0,0.0,1.0}, {0.0,1.0,1.0}};

GLfloat st[][3]=
    {{1.8,-1.5,-1.0}, {2.0,-1.5,-1.0}, {2.0,0.9,-1.0}, {1.8,0.9,-1.0},
     {1.7,-1.6, 1.0}, {1.9,-1.6, 1.0}, {1.9,0.8, 1.0}, {1.7,0.8, 1.0}};

GLint i, h, m, k, n = 5;
GLfloat tempv[8][3];
GLint tos = -1, maxsize = 5, g = -1, f = 0, ch, fr = -1, r = -1;
GLfloat tempst = -1.5, sttos = -1.9;
GLfloat stcube[9][8][3];
GLint pu = 0, po = 0, in = 0, l, o, rear, node = 0;
GLfloat tx = 0.0, ty = 1.0, stfr = -1.5, str = -1.4;
int out = 0;



void polygon(int a,int b,int c,int d,int i) {
    glBegin(GL_POLYGON);
    glColor3fv(colors[a]); glVertex3fv(v[i][a]);
    glColor3fv(colors[b]); glVertex3fv(v[i][b]);
    glColor3fv(colors[c]); glVertex3fv(v[i][c]);
    glColor3fv(colors[d]); glVertex3fv(v[i][d]);
    //glFlush();                      // force execution of GL commands in finite time
    glEnd();
}



void colorcube() {
    polygon(0,3,2,1,i);
    polygon(2,3,7,6,i);
    polygon(0,4,7,3,i);
    polygon(1,2,6,5,i);
    polygon(4,5,6,7,i);
    polygon(0,1,5,4,i);
}



void stack(int a,int b,int c,int d) {
    glBegin(GL_POLYGON);
    glColor3f(1.0,1.0,1.0); glVertex3fv(st[a]);
    glColor3fv(colors[b]);  glVertex3fv(st[b]);
    glColor3f(1.0,1.0,1.0); glVertex3fv(st[c]);
    glColor3fv(colors[d]);  glVertex3fv(st[d]);
    //glFlush();
    glEnd();
}



void stackcube() {
    stack(0,3,2,1);
    stack(2,3,7,6);
    stack(0,4,7,3);
    stack(1,2,6,5);
    stack(4,5,6,7);
    stack(0,1,5,4);
}



void resultpolygon(int a,int b,int c,int d) {
    glBegin(GL_POLYGON);
    glColor3fv(colors[a]); glVertex3fv(tempv[a]);
    glColor3fv(colors[b]); glVertex3fv(tempv[b]);
    glColor3fv(colors[c]); glVertex3fv(tempv[c]);
    glColor3fv(colors[d]); glVertex3fv(tempv[d]);
    //glFlush();
    glEnd();
}



void resultcolorcube() {
    resultpolygon(0,3,2,1);
    resultpolygon(2,3,7,6);
    resultpolygon(0,4,7,3);
    resultpolygon(1,2,6,5);
    resultpolygon(4,5,6,7);
    resultpolygon(0,1,5,4);
}



void stackpolygon(int a,int b,int c,int d,int f) {
    glBegin(GL_POLYGON);
    glColor3fv(colors[a]); glVertex3fv(stcube[f][a]);
    glColor3fv(colors[b]); glVertex3fv(stcube[f][b]);
    glColor3fv(colors[c]); glVertex3fv(stcube[f][c]);
    glColor3fv(colors[d]); glVertex3fv(stcube[f][d]);
    //glFlush();
    glEnd();
}



void stackcolorcube() {
    stackpolygon(0,3,2,1,f);
    stackpolygon(2,3,7,6,f);
    stackpolygon(0,4,7,3,f);
    stackpolygon(1,2,6,5,f);
    stackpolygon(4,5,6,7,f);
    stackpolygon(0,1,5,4,f);
}



void init() {
    glClearColor(0.1,0.1,0.1,1.0);
    gluOrtho2D(0.0,599.0,0.0,599.0);
}



void text(char str[]) {
    int i;
    for(i=0; i<strlen(str); i++) {
        glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,str[i]);
    }
}



void form2() {
    glColor3f(0.8,0.2,0.7);
    glRasterPos3f(-1.6,0.85,-1.0);
    text("1. Press 1 to goto Stack");
    glRasterPos3f(-1.8,1.45,-1.0);
    text("NAVIGATION OPTIONS");
    glRasterPos3f(-1.6,0.55,-1.0);
    text("2. Press 2 to goto Queue");
    glRasterPos3f(-1.6,-0.05,-1.0);
    text("4. Press 4 to exit");
    //glFlush();
    glEnd();
}



void display() {
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    if(out==0)
        form2();

    else {
        if(ch==1) {
            glColor3f(0.8,0.2,0.7);
            if(sttos<-1.5)    //position of the tos near storage block
                glRasterPos3f(1.45,sttos+0.4,1.0);
            else
                glRasterPos3f(1.45,sttos,1.0);
            text("tos>>");
            //glFlush();
            for(i=0; i<=n; i++)
                colorcube();   //stack small block
            stackcube();   //stack storage block
            resultcolorcube();  //small block movement ray into storage block
            for(f=0; f<=tos; f++)
                stackcolorcube();   //display of the small block in stotage block
            glColor3f(0.8,0.2,0.7);
            glRasterPos3f(1.7,-1.8,1.0);
            text("Stack");
            //glFlush();
            if(tos==-1) {
                glColor3f(0.8,0.2,0.7);
                glRasterPos3f(-0.5,0.0,-1.0);
                text("Stack Empty");
                //glFlush();
            }
            if(tos>=maxsize) {
                glColor3f(0.8,0.2,0.7);
                glRasterPos3f(-0.5,0.0,-1.0);
                text("Stack Full");
                //glFlush();
            }
        } else if(ch==2) {
            glColor3f(1.0,0.0,0.0);
            glRasterPos3f(1.38,stfr,1.0);
            text("front>>");
            //glFlush();

            glColor3f(1.0,0.0,0.0);
            glRasterPos3f(1.4,str,1.0);
            text("rear>>");
            //glFlush();

            glColor3f(0.8,0.2,0.7);
            glRasterPos3f(2.1,-0.2,1.0);
            glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,'Q');
            glRasterPos3f(2.1,-0.35,1.0);
            glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,'u');
            glRasterPos3f(2.1,-0.5,1.0);
            glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,'e');
            glRasterPos3f(2.1,-0.65,1.0);
            glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,'u');
            glRasterPos3f(2.1,-0.8,1.0);
            glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,'e');
            //glFlush();
            for(i=0; i<=n; i++)
                colorcube();
            stackcube();
            resultcolorcube();
            for(f=fr; f<=r; f++)
                stackcolorcube();
            if(r==-1) {
                glColor3f(0.8,0.2,0.7);
                glRasterPos3f(-0.5,0.0,-1.0);
                text("Queue Empty");
                //glFlush();
            }
            if(r>=maxsize) {
                glColor3f(0.8,0.2,0.7);
                glRasterPos3f(-0.5,0.0,-1.0);
                text("Queue Full");
                //glFlush();
            }
        }

        glColor3f(0.5,0.6,0.8);
        glRasterPos3f(-0.5,1.45,-1.0);
        text("Press m/M to goto Main Menu");
        //glFlush();
    }
    if(ch==4)
        exit(0);
    glutSwapBuffers();

}



void myreshape(int w,int h) {
    glViewport(0,0,w,h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    if(w<=h)
        glOrtho(-2.0,2.0,-2.0*(GLfloat)h/(GLfloat)w,2.0*(GLfloat)h/(GLfloat)w,-10.0,10.0);
    else
        glOrtho(-2.0*(GLfloat)w/(GLfloat)h,2.0*(GLfloat)w/(GLfloat)h,-2.0,2.0,-10.0,10.0);
    glMatrixMode(GL_MODELVIEW);
}



void push() {
    if(tos<maxsize) {
        for(h=0; h<8; h++)
            for(m=0; m<3; m++)
                tempv[h][m]=v[i][h][m];
        n--;
        display();
        while(tempv[0][1]<=1.0) {
            for(k=0; k<8; k++)
                tempv[k][1]=tempv[k][1]+0.1;
            display();
        }
        while(tempv[0][0]<=st[0][0]) {
            for(k=0; k<8; k++)
                tempv[k][0]=tempv[k][0]+0.1;
            display();
        }
        while(tempv[0][1]>tempst) {
            for(k=0; k<8; k++)
                tempv[k][1]=tempv[k][1]-0.1;
            display();
        }
        tos++;
        for(h=0; h<8; h++)
            for(m=0; m<3; m++)
                stcube[tos][h][m]=tempv[h][m];
        tempst+=0.4;
        sttos+=0.4;
        display();
    } else {
        display();
    }
}



void pop() {
    if(tos>=0) {
        for(h=0; h<8; h++)
            for(m=0; m<3; m++)
                tempv[h][m]=stcube[tos][h][m];
        tos--;
        display();
        while(tempv[0][1]<=1.0) {
            for(k=0; k<8; k++)
                tempv[k][1]=tempv[k][1]+0.1;
            display();
        }
        while(tempv[0][0]>v[i][0][0]) {
            for(k=0; k<8; k++)
                tempv[k][0]=tempv[k][0]-0.1;
            display();
        }
        while(tempv[0][1]>v[i][0][1]) {
            for(k=0; k<8; k++)
                tempv[k][1]=tempv[k][1]-0.1;
            display();
        }
        tempst-=0.4;
        display();
        sttos-=0.4;
        n++;
        display();
    } else {
        display();
    }
}



void stack_menu(int id) {
    switch(id) {
    case 1:
        i--;
        push();
        break;
    case 2:
        pop();
        break;
    case 4:
        exit(0);
        break;
    }
}



void mymenu() {
    glutCreateMenu(stack_menu);
    glutAddMenuEntry("Push",1);
    glutAddMenuEntry("Pop",2);
    glutAddMenuEntry("Exit",4);
    glutAttachMenu(GLUT_RIGHT_BUTTON);
}



void insert() {
    if(r>=maxsize)
        display();
    else {
        for(h=0; h<8; h++)
            for(m=0; m<3; m++)
                tempv[h][m]=v[i][h][m];
        n--;
        display();
        while(tempv[0][1]<=1.0) {
            for(k=0; k<8; k++)
                tempv[k][1]=tempv[k][1]+0.1;
            display();
        }
        while(tempv[0][0]<=st[0][0]) {
            for(k=0; k<8; k++)
                tempv[k][0]=tempv[k][0]+0.1;
            display();
        }
        while(tempv[0][1]>tempst) {
            for(k=0; k<8; k++)
                tempv[k][1]=tempv[k][1]-0.1;
            display();
        }
        tempst+=0.4;
        r++;
        for(h=0; h<8; h++)
            for(m=0; m<3; m++)
                stcube[r][h][m]=tempv[h][m];
        display();
        str+=0.4;
        if(r==maxsize)
            str-=0.4;
        if(fr==-1)
            fr=0;
    }
}



void _remove() {
    if(fr==-1)
        display();
    else if(fr<=r) {
        for(h=0; h<8; h++)
            for(m=0; m<3; m++)
                tempv[h][m]=stcube[fr][h][m];
        fr++;
        display();
        stfr+=0.4;
        if(fr>r)
            stfr-=0.4;
        while(tempv[0][1]>-1.8) {
            for(k=0; k<8; k++)
                tempv[k][1]=tempv[k][1]-0.1;
            display();
        }
        while(tempv[0][0]>0.0) {
            for(k=0; k<8; k++)
                tempv[k][0]=tempv[k][0]-0.1;
            display();
        }
        while(tempv[0][1]<1.0) {
            for(k=0; k<8; k++)
                tempv[k][1]=tempv[k][1]+0.1;
            display();
        }
        while(tempv[0][0]>v[i][0][0]) {
            for(k=0; k<8; k++)
                tempv[k][0]=tempv[k][0]-0.1;
            display();
        }
        while(tempv[0][1]>v[i][0][1]) {
            for(k=0; k<8; k++)
                tempv[k][1]=tempv[k][1]-0.1;
            display();
        }
        if(fr>r) {
            fr=-1;
            r=-1;
            tempst=-1.5;
            str=-1.4;
            stfr=-1.5;
        }
        n++;
        display();
    }
}



void queuemenu(int id) {
    switch(id) {
    case 1:
        i--;
        insert();
        break;
    case 2:
        _remove();
        break;
    case 4:
        break;
        exit(0);
    }
}



void myqmenu() {
    glutCreateMenu(queuemenu);
    glutAddMenuEntry("Insert",1);
    glutAddMenuEntry("Remove",2);
    glutAddMenuEntry("Exit",4);
    glutAttachMenu(GLUT_RIGHT_BUTTON);
}



void keyboard(unsigned char key,int x,int y) {
    if(key=='1') {
        out=3;
        ch=1;
        n=5;
        i=0;
        tos=-1;
        sttos=-1.9;
        tempst=-1.5;
        mymenu();
        display();
    }
    if(key=='2') {
        out=3;
        ch=2;
        n=5;
        i=0;
        r=fr=-1;
        stfr=-1.5;
        str=-1.4;
        tempst=-1.5;
        myqmenu();
        display();
    }
    if(key=='4') {
        exit(0);
    }
    if(key=='m'||key=='M') {
        out=0;
        display();
    }
}



int main(int argc,char **argv) {
    glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB|GLUT_DEPTH);
    glutInitWindowSize(600,600);
    glutCreateWindow("colorcube");
    init();
    glutKeyboardFunc(keyboard);
    glutReshapeFunc(myreshape);
    glutDisplayFunc(display);
    glutMainLoop();
    return 0;
}

Secondly, one-letter global variables are evil. In fact, any modifiable globals (especially with non-descriptive names) are. They should be avioded whenever possible.
Thirdly, you are abusing glFlush(). Theres virtually no need to insert it when you already have glutSwapBuffers(), let alone between glBegin() and glEnd(). And finally, it may be just me, but I dont quite understand what you are trying to do. If you want to draw some data structure then add this data structure to the program and do whatever you want with it. It doesn`t have to contain anything OpenGL-related, since you may read it directly while rendering and emit any appropriate OpenGL primitives on the fly.