How to use character value in if condition (c++) - c++

Question

{
cout << "type 3 to add ,type 1 to multiply,type division to divide,type 2 to subtract" << endl;
cin >> function;
if (function == 1)
{
multiply();
}
else if (function == 2)
{
subtract();
}
else if (function == 3)
{
add();
}
else if (function == 4)
{
division();
}
cout << "press x to quit or anything else to restart " << endl;
cin >> input;
} while (input !='x');
system("pause");
return 0;
}
in this code i am unable to have a character value with if
eg-if (function=='add') it does not work
if I use if(function='add') everything inside is skipped to the last cout which says
press x to quit or anything else to restart

Answer 1

'add' is a multicharacter literal and is an int type (note the single quotation characters). You almost certainly don't want to do that as then you're in the murky waters of implementation-defined behaviour.
If you want to be able to read in strings then why not use a std::string as the type for function, and use if (function == "add") &c. ? You can even retain your notation cin >> function!

Answer 2

As suggested by Bathsheba, you could implement this functionality with std::string. Bellow you have an example of how you could do this.
#include <iostream>
#include <string>
void multiply() {
std::cout << "multiplication called" << std::endl;
}
void add() {
std::cout << "add called" << std::endl;
}
void subtract() {
std::cout << "substract called" << std::endl;
}
void division() {
std::cout << "division called" << std::endl;
}
int main()
{
using namespace std;
string input;
do {
cout << "type add, multiply, division, or subtract" << endl;
cin >> input;
if (input == "multiply") {
multiply();
}
else if (input == "substract") {
subtract();
}
else if (input == "add") {
add();
}
else if (input == "division") {
division();
}
else {
cout << "You inputed: " << input << endl;
cout << "Command not recognized, please try again" << endl;
continue;
}
cout << "press x to quit or anything else to restart ";
cin >> input;
} while (input != "x");
return 0;
}