/in/foo.c: In function 'main':
/in/foo.c:10:12: warning: format '%c' expects argument of type 'char *', but argument 2 has type 'int' [-Wformat=]
    scanf("%c", str[i][j]);
            ^
/in/foo.c:13:11: warning: format '%c' expects argument of type 'char *', but argument 2 has type 'int' [-Wformat=]
   scanf("%c", substr[j]);
           ^