foo.c: In function 'main':
foo.c:6:29: warning: unused variable 'num1' [-Wunused-variable]
  int x,y,k,num=0,a[100],m=0,num1=0;
                             ^~~~
foo.c:6:25: warning: unused variable 'm' [-Wunused-variable]
  int x,y,k,num=0,a[100],m=0,num1=0;
                         ^
foo.c:6:18: warning: unused variable 'a' [-Wunused-variable]
  int x,y,k,num=0,a[100],m=0,num1=0;
                  ^
foo.c:7:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&x,&y);//求一个数有几种因子
  ^~~~~~~~~~~~~~~~~~~