foo.cc: In function 'int main()':
foo.cc:9:6: error: redeclaration of 'int cnt'
  int cnt=0;
      ^~~
foo.cc:7:10: note: 'int cnt' previously declared here
  int a,b,cnt;
          ^~~
foo.cc:16:14: error: 'k' was not declared in this scope
    if(xx%10==k)
              ^