/in/foo.cc: In function 'void work()':
/in/foo.cc:137:6: warning: unused variable 'i' [-Wunused-variable]
  int i,j,l,r,mid;
      ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:172:6: warning: unused variable 'i' [-Wunused-variable]
  int i,j;
      ^
/in/foo.cc:172:8: warning: unused variable 'j' [-Wunused-variable]
  int i,j;
        ^
/in/foo.cc:180:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d",&m);
                  ^
/in/foo.cc:202:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s",ch);
                 ^