#include <stdio.h>
 
int main() {
 
  char op;
  double first, second;
  printf("Enter an operator (+, -, *, /): ");
  scanf("%c", &op);
  printf("Enter two operands: ");
  scanf("%lf %lf", &first, &second);
 
  switch (op) {
    case '+':
      printf("%.1lf + %.1lf = %.1lf", first, second, first + second);
      break;
    case '-':
      printf("%.1lf - %.1lf = %.1lf", first, second, first - second);
      break;
    case '*':
      printf("%.1lf * %.1lf = %.1lf", first, second, first * second);
      break;
    case '/':
      printf("%.1lf / %.1lf = %.1lf", first, second, first / second);
      break;
    // operator doesn't match any case constant
    default:
      printf("Error! operator is not correct");
  }
 
  return 0;
}

I2luY2x1ZGUgPHN0ZGlvLmg+CgppbnQgbWFpbigpIHsKCiAgY2hhciBvcDsKICBkb3VibGUgZmlyc3QsIHNlY29uZDsKICBwcmludGYoIkVudGVyIGFuIG9wZXJhdG9yICgrLCAtLCAqLCAvKTogIik7CiAgc2NhbmYoIiVjIiwgJm9wKTsKICBwcmludGYoIkVudGVyIHR3byBvcGVyYW5kczogIik7CiAgc2NhbmYoIiVsZiAlbGYiLCAmZmlyc3QsICZzZWNvbmQpOwoKICBzd2l0Y2ggKG9wKSB7CiAgICBjYXNlICcrJzoKICAgICAgcHJpbnRmKCIlLjFsZiArICUuMWxmID0gJS4xbGYiLCBmaXJzdCwgc2Vjb25kLCBmaXJzdCArIHNlY29uZCk7CiAgICAgIGJyZWFrOwogICAgY2FzZSAnLSc6CiAgICAgIHByaW50ZigiJS4xbGYgLSAlLjFsZiA9ICUuMWxmIiwgZmlyc3QsIHNlY29uZCwgZmlyc3QgLSBzZWNvbmQpOwogICAgICBicmVhazsKICAgIGNhc2UgJyonOgogICAgICBwcmludGYoIiUuMWxmICogJS4xbGYgPSAlLjFsZiIsIGZpcnN0LCBzZWNvbmQsIGZpcnN0ICogc2Vjb25kKTsKICAgICAgYnJlYWs7CiAgICBjYXNlICcvJzoKICAgICAgcHJpbnRmKCIlLjFsZiAvICUuMWxmID0gJS4xbGYiLCBmaXJzdCwgc2Vjb25kLCBmaXJzdCAvIHNlY29uZCk7CiAgICAgIGJyZWFrOwogICAgLy8gb3BlcmF0b3IgZG9lc24ndCBtYXRjaCBhbnkgY2FzZSBjb25zdGFudAogICAgZGVmYXVsdDoKICAgICAgcHJpbnRmKCJFcnJvciEgb3BlcmF0b3IgaXMgbm90IGNvcnJlY3QiKTsKICB9CgogIHJldHVybiAwOwp9

KwoxIDI=

+
1 2