foo.cc: In function 'int main()':
foo.cc:32:24: warning: unused variable 'cnt' [-Wunused-variable]
   int tmp=check(i,j,k),cnt=tmp;
                        ^~~
foo.cc: In function 'int check(int, int, int)':
foo.cc:11:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
foo.cc: In function 'int check2(int, int, int)':
foo.cc:20:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^