/in/foo.cc: In function 'int main()':
/in/foo.cc:6:8: warning: unused variable 'n1' [-Wunused-variable]
  int n,n1=1,cnt=0;//n1是阶乘结果 
        ^~
/in/foo.cc:6:13: warning: unused variable 'cnt' [-Wunused-variable]
  int n,n1=1,cnt=0;//n1是阶乘结果 
             ^~~
/in/foo.cc: In function 'int sjc(int)':
/in/foo.cc:25:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^