/in/foo.cc: In function 'int main()':
/in/foo.cc:7:9: warning: unused variable 'a' [-Wunused-variable]
 int n,m,a,b,c,s1,s2,s3,i;
         ^
/in/foo.cc:7:11: warning: unused variable 'b' [-Wunused-variable]
 int n,m,a,b,c,s1,s2,s3,i;
           ^
/in/foo.cc:7:13: warning: unused variable 'c' [-Wunused-variable]
 int n,m,a,b,c,s1,s2,s3,i;
             ^
/in/foo.cc:7:18: warning: variable 's2' set but not used [-Wunused-but-set-variable]
 int n,m,a,b,c,s1,s2,s3,i;
                  ^~
/in/foo.cc:7:21: warning: variable 's3' set but not used [-Wunused-but-set-variable]
 int n,m,a,b,c,s1,s2,s3,i;
                     ^~