prog.c: In function ‘main’:
prog.c:4:16: error: ‘x’ undeclared (first use in this function)
scanf("%d %d",&x,&y);
^
prog.c:4:16: note: each undeclared identifier is reported only once for each function it appears in
prog.c:4:19: error: ‘y’ undeclared (first use in this function)
scanf("%d %d",&x,&y);
^