/in/foo.c: In function 'main':
/in/foo.c:18:18: warning: unused variable 'a' [-Wunused-variable]
  int n,i,m,j=0,b,a,sum=0;
                  ^
/in/foo.c:18:16: warning: unused variable 'b' [-Wunused-variable]
  int n,i,m,j=0,b,a,sum=0;
                ^
/in/foo.c:18:12: warning: unused variable 'j' [-Wunused-variable]
  int n,i,m,j=0,b,a,sum=0;
            ^
/in/foo.c:18:10: warning: unused variable 'm' [-Wunused-variable]
  int n,i,m,j=0,b,a,sum=0;
          ^