如何使用if else语句

Question

Today I want to test if a user types the word "yes" in console application, then the function will proceed, however, I am unable to do so. (I am a new person, sorry)

Any help on this? I know when testing a variable like.. int x = 14, and if (a < 14) print something.. but instead of number I'd like to try with text.

Here is the source code:

int main()
 {
   char a = yes;
   char b = no;
   cout << "hi, press yes to start or no to cancel";
   cin >> a;

  if (a == yes)
   { 
  cout << "Cool person";
   }
  else if(b == no)
   {
  cout << "not a cool person";
  }
}

I keep getting "yes" is not defined in scope. Any help would be appreciated. Thank You!

Answer 1

At a bare minimum, the following problems exist in your code:

• Tokens yes and no are identifiers. If you wanted them to be characters, that would be 'yes' and 'no . Except that they're not characters since they're too long. So, they should probably be strings like "yes" and "no" .

• The b variable is totally useless here, you should have one variable for receiving information from the user and checking it against multiple possible values. It's also a good idea to choose meaningful variable names.

• You aren't including the requisite headers, nor are you using the correct namespace for the std functions and types (either by explicitly prepending std:: to each, or with a using namespace std for them all).

With that in mind, try out the following program as a starting point for your further education:

#include <iostream>
#include <string>

int main() {
    std::string userInput;

    std::cout << "Hi, enter yes to start or no to cancel: ";
    std::cin >> userInput; // probably better: std::getline(std::cin, userInput);

    if (userInput == "yes") {
        std::cout << "Cool person\n";
    } else if (userInput == "no") {
        std::cout << "Not a cool person\n";
    } else {
        std::cout << "Hey, can't you read? I said yes or no :-)\n";
    }
}