foo.cc: In function ‘int main()’:
foo.cc:9:17: warning: unused variable ‘j’ [-Wunused-variable]
    9 |     int n,ans,i,j;char c;string s;
      |                 ^
foo.cc:31:11: warning: ‘ans’ may be used uninitialized [-Wmaybe-uninitialized]
   31 |     printf("%d",ans);
      |     ~~~~~~^~~~~~~~~~
foo.cc:9:11: note: ‘ans’ was declared here
    9 |     int n,ans,i,j;char c;string s;
      |           ^~~