/in/foo.cc: In function 'int main()':
/in/foo.cc:15:23: warning: format '%lf' expects argument of type 'double*', but argument 2 has type 'int*' [-Wformat=]
   scanf("%lf",&a[i][j]);
                       ^
/in/foo.cc:18:19: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printf("%.2lf",c);
                   ^