/in/foo.c: In function 'main':
/in/foo.c:25:17: warning: comparison between pointer and integer
   for(int i=0; i<r; i++)
                 ^
/in/foo.c:26:11: error: subscripted value is neither array nor pointer nor vector
    if(c[0][i]!=0||c[C-1][i]!=0) break;
           ^
/in/foo.c:26:25: error: subscripted value is neither array nor pointer nor vector
    if(c[0][i]!=0||c[C-1][i]!=0) break;
                         ^
/in/foo.c:24:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(c[high]==C/2)
  ^~
/in/foo.c:27:3: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   if(r==i) min=r[high];
   ^~
/in/foo.c:27:9: error: 'i' undeclared (first use in this function)
   if(r==i) min=r[high];
         ^
/in/foo.c:27:9: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:14:6: warning: variable 'a' set but not used [-Wunused-but-set-variable]
  int a[100][100];
      ^