/in/foo.cc:2:11: error: '::main' must return 'int'
 void main()
           ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:6:14: error: 'scanf' was not declared in this scope
 scanf("%d",&n);
              ^
/in/foo.cc:28:20: error: 'printf' was not declared in this scope
 printf("%c",str2[m]);
                    ^
/in/foo.cc:29:28: error: 'printf' was not declared in this scope
 printf("\n%d\n%d\n",max,sum);
                            ^