Can't compile example from text book. 3 errors.

[eiger3970]

Hi,
my code below is similar to an example on a previous page in the text book which compiles.
For 1 error reason, this text book example has a lot of mistakes that won't compile and I need some help to fix it.
1 error:
main.cpp: In function ‘void polyline(GLint, GLint, GLint, GLint)’:
main.cpp:50:9: error: ‘ptCtr’ was not declared in this scope


Code:

#include <GL/glut.h>
 
GLsizei winWidth = 400, winHeight = 300;        // Initial display-window size.
GLint endPtCtr = 0;                             // Initialise line endpoint counter.
 
class scrPt
{
public:
    GLint x, y;
};
 
void init (void)
{
    glClearColor (0.0, 0.0, 1.0, 1.0)           // Set display-window colour to blue.
 
    glMatrixMode (GL_PROJECTION);
    gluOrtho2D (0.0, 200.0, 0.0, 150.0);
}
 
void displayFcn (void)
{
    glClear (GL_COLOR_BUFFER_BIT);
}
 
void winReshapeFcn (GLint newWidth, GLint newHeight)
{
    /* Reset viewport and projection parameters. */
    glViewport (0, 0, newWidth, newHeight);
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity ( );
    gluOrtho2D (0.0, GLdouble (newWidth), 0.0, GLdouble (newHeight));
 
    /* Reset display-window size parameters. */
    winWidth = newWidth;
    winHeight = newHeight;
}
 
void drawLineSegment (scrPt endPt1, scrPt endPt2)
{
    glBegin (GL_LINES);
        glVertex2i (endPt1.x, endPt1.y);
        glVertex2i (endPt2.x, endPt2.y);
    glEnd( );
}
 
void polyline (GLint button, GLint action, GLint xMouse, GLint yMouse)
{
    static scrPt endPt1, endPt2;
 
    if (ptCtr == 0)
    {
        if (button == GLUT_LEFT_BUTTON && action == GLUT_DOWN)
        {
            endPt1.x = xMouse;
            endPt1.y = winHeight - yMouse;
            ptCtr = 1;
        }
        else
            if (button == GLUT_RIGHT_BUTTON)    // Quit the program.
                exit (0);
    }
    else
        if (button == GLUT_LEFT_BUTTON && action == GLUT_DOWN)
        {
            endPt2.x = xMouse;
            endPt2.y = winHeight - yMouse;
            drawLineSegment (endPt1, endPt2);
 
            endPt1 = endPt2;
        }
        else
            if (button = GLUT_RIGHT_BUTTON)     // Quit the program.
                exit (0);
 
    glFlush ( );
}
 
void main (int argc, char** argv)
{
    glutInit (&argc, argv);
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
    glutInitWindowPosition (100, 100);
    glutInitWindowSize (winWidth, winHeight);
    glutCreateWindow ("Draw Interactive Polyline");
 
    init ( );
    glutDisplayFunc (displayFcn);
    glutReshapeFunc (winReshapeFcn);
    glutMouseFunc (polyline);
 
    glutMainLoop ( );
}

[tonyo_au]

A quick look it seems ptCtr should be endPtCtr - but the compiler is correct it is not defined.

Please enclose code is side "square-bracket code square-bracket" "square-bracket /code square-bracket" when posting

EDIT: I would be very doubtful about using a book with that many errors

[Dark Photon]

Please enclose code is side "square-bracket code square-bracket" "square-bracket /code square-bracket" when posting

The [noparse] tag is very useful for telling folks about VBulletin markup - discovered that a few months ago. For instance:

Please enclose code inside [code]...[/code] blocks when posting (or use [highlight=cpp]...[/highlight] or [highlight=glsl]...[/highlight] if you want colorization as well).

[tonyo_au]

Thanks for that