переменные — C ++ константный символ

Я построил простой калькулятор из c ++, он использует символы, поэтому (+, — *, /) будет работать как математические операторы, но когда пользователь вводит ‘=’, он не работает.

#include <iostream>
#include <string>
#include <sstream>
#include <math.h>
using namespace std;

#define PI 3.14159265359
#define NEWLINE '\n'void printf(string string)
{
cout << string;
}

int main ()
{
char operation;
double a,b,c, value;
double answer = 0;
bool more = true;

cout << "Welcome to My Calculator\n\nInput a value: ";
cin >> answer;
operations:

cin >> operation;

if (operation != '=') {
if (operation == '+') {
cin >> value;
cout << "\n" << answer << " " << operation << " " << value << "\n";
answer += value;
cout << "Equals " << answer << "\n";
cout << answer << " - New Operation? ";
goto operations;
}
if (operation == '-') {
cin >> value;
cout << "\n" << answer << " " << operation << " " << value << "\n";
answer -= value;
cout << "Equals " << answer << "\n";
cout << answer << " - New Operation? ";
goto operations;
}
if (operation == '*') {
cin >> value;
cout << "\n" << answer << " " << operation << " " << value << "\n";
answer *= value;
cout << "Equals " << answer << "\n\n";
cout << answer << " - New Operation? ";
goto operations;
}
if (operation == '/') {
cin >> value;
cout << "\n" << answer << " " << operation << " " << value << "\n";
answer /= value;
cout << "Equals " << answer << "\n\n";
cout << answer << " - New Operation? ";
goto operations;
}
if (operation == '^') {
cin >> value;
cout << "\n" << answer << " " << operation << " " << value << "\n";
answer = pow(answer, value);
cout << "Equals " << answer << "\n\n";
cout << answer << " - New Operation? ";
goto operations;
}
if (operation == '=') {
cout << "\nFinal Answer = " << answer << "\n\nNew operation [yes/no]: ";
string check;
cin >> check;
if (check == "yes") {
cout << "\nInput value: ";
cin >> answer;
cout << "\n";
goto operations;
} else {
cout << "\nGoodbye for now...\n";
return 0;
}

}
} else {
cout << "Unknown Error! Program Closing...";
return 0;
}return 0;
}

Когда пользователь использует какую-либо операцию, кроме =, она работает отлично, но если я использую знак равенства, он не работает.

Пример программы на выходе:

Welcome to My Calculator

Input a value: 4
+4

4 + 4
Equals 8
8 - New Operation? - 3

8 - 3
Equals 5
5 - New Operation? * 5

5 * 5
Equals 25

25 - New Operation? /2

25 / 2
Equals 12.5

12.5 - New Operation? ^2

12.5 ^ 2
Equals 156.25

156.25 - New Operation? =
Unknown Error! Program Closing...