c - Moving a circle along the X-axis -

i making circle move in x direction only. have drawn circle, not able move in x direction. missing anything?

void display() {     int count=0;                      //counter checking purpose      glclear(gl_color_buffer_bit);     drawcircle(xxc,yyc,rr);           //draws circle     glflush();     xxc=xxc+deltax;                   //increment x coordinate      printf("%d",count);               //prints value of count      if(xxc>100 || xxc<0 ) {           //to move between 100 , 0         deltax=-deltax;               //for , fro motion of circle     }     count++;                          //increment count     glutpostredisplay();    }