OpenGL: Error moving object using keyboard -

i'm new opengl , i'm trying paint stickman , move using arrow-keys keyboard. idea use global variables stickman , change them when key pressed. afterwards draw-function (mydisplay()) called again. unfortunately following error-message: "error 10 error c2371: 'mydisplay' : redefinition; different basic types " when replace mydisplay()-call in keyboard-function glutpostredisplay() suggested in tutorials read error message disapears , build successful. stickman doesn't move when pressing keys.

here's code:

#include <gl/glut.h>  glint x; glint y; glint d;  //parameters stickman  void mykeyboard(unsigned char key, int mx, int my) {     int x1 = mx;     int y1 = 480 - my;      switch(key){     case glut_key_left :         x = x-50;         mydisplay();         break;     case 'e' :          exit(-1);         break;     default:          break;     } }   void stickman () {     glbegin(gl_lines);          //body         glvertex2i(x, y);         glvertex2i(x, y-2*d);         glvertex2i(x-d, y-d);         glvertex2i(x+d, y-d);         glvertex2i(x, y-2*d);         glvertex2i(x-d, y-3*d);         glvertex2i(x, y-2*d);         glvertex2i(x+d, y-3*d);     glend();      glbegin(gl_line_loop);      //head         glvertex2i(x,y);         glvertex2i(x+0.5*d, y);         glvertex2i(x+0.5*d, y+0.5*d);         glvertex2i(x-0.5*d, y+0.5*d);         glvertex2i(x-0.5*d, y);     glend(); }   void mydisplay() {     glclear(gl_color_buffer_bit);     glcolor3f(0.0, 0.0, 0.0);      stickman();      glflush(); }  void myinit() {     glclearcolor(1.0, 1.0, 1.0, 1.0);     glmatrixmode(gl_projection);     glloadidentity();     gluortho2d(0.0, 640.0, 0.0, 480.0); }  void main(int argc, char** argv) {     x = 320;     y = 350;     d = 100;      glutinit(&argc, argv);     glutinitdisplaymode(glut_single | glut_rgb);     glutinitwindowsize(640, 480);     glutinitwindowposition(200, 50);     glutcreatewindow("stickman");     glutdisplayfunc(mydisplay);     glutkeyboardfunc(mykeyboard);     glutpostredisplay();     myinit();     glutmainloop(); } 

as found out (glut keyboard tutorial) problem wasn't repaint of picture, rather left arrow key wasn't recognized. needed write keyboard-function special keys such arrow keys.

now code looks , works:

void processnormalkeys (unsigned char key, int mx, int my) {     if (key == 'e')         exit(-1);    }  void processspecialkeys (int key, int mx, int my) {     switch(key){     case glut_key_left :         x = x-5;         glutpostredisplay();         break;     case glut_key_right :         x = x+5;         glutpostredisplay();         break;     case glut_key_up :         y = y+5;         glutpostredisplay();         break;     case glut_key_down :         y = y-5;         glutpostredisplay();         break;     default:          break;     } } 

i had adjust main function:

glutkeyboardfunc(processnormalkeys); glutspecialfunc(processspecialkeys); 

but anyways!