请大家指点！

int max(int a,int b); main() { int x,y,z; printf("input two numbers:\n"); scanf("%d,%d",&x,&y); z=max(x,y); printf("maxnum=%d",z); getch(); } int max(int a,int b) { if(a>b) return a; if (a<b) return b; else { printf("a=b\n"); return a; } }