C++ error when running code - c++

Question

I'm trying to learn C++ and i cant figure a problem out.
My code:
#include <iostream>
using namespace std;
int userContinue = true;
int userContinueString;
int getUserInput() {
int userInput1;
int userInput2;
cout << "Please enter your first number: ";
cin >> userInput1;
cout << endl << "Please enter your second number: ";
cin >> userInput2;
cout << endl << "The result of the two numbers together: " << userInput1+userInput2;
userInput1 = 0;
userInput2 = 0;
return 0;
}
int main()
{
while (userContinue == true) {
getUserInput();
cout << endl << "Would you like to continue? (Y/N): ";
cin >> userContinueString;
if (userContinueString ='Y') {
}
else {
userContinue = false;
}
}
return 0;
}
The code works fine until i input "Y" ant then it keeps looping as shown here: Video

Answer 1

First, make sure you compile your code with some warning switches such as -Wall -Wpedantic. These switches will help you. For instance, in your original code, my compiler prints the following warnings:
prog.cpp:25:28: warning: using the result of an assignment as a condition without parentheses [-Wparentheses]
if (userContinueString = 'Y') {
~~~~~~~~~~~~~~~~~~~^~~~~
prog.cpp:25:28: note: place parentheses around the assignment to silence this warning
if (userContinueString = 'Y') {
^
( )
prog.cpp:25:28: note: use '==' to turn this assignment into an equality comparison
if (userContinueString = 'Y') {
^
==
1 warning generated.
Then, I fix the corresponding line with ==, which was already suggested in the comments. Then, your comparison should be case-insensitive. Finally, you would like to compare character objects with respect to 'y' or 'Y':
#include <cctype>
#include <iostream>
using namespace std;
int userContinue = true;
char /* not int */ userContinueString;
int getUserInput() {
int userInput1;
int userInput2;
cout << "Please enter your first number: ";
cin >> userInput1;
cout << endl << "Please enter your second number: ";
cin >> userInput2;
cout << endl
<< "The result of the two numbers together: " << userInput1 + userInput2;
userInput1 = 0;
userInput2 = 0;
return 0;
}
int main() {
while (userContinue == true) {
getUserInput();
cout << endl << "Would you like to continue? (Y/N): ";
cin >> userContinueString;
if (std::tolower(userContinueString) == 'y') {
} else {
userContinue = false;
}
}
return 0;
}
EDIT. I have improved the answer by taking into account David's comment below. Note the use of #include <cctype> and std::tolower.
EDIT. I have tried improving the answer further by trying to address the "learning C++" comment below:
#include <functional>
#include <iostream>
#include <sstream>
#include <string>
#include <type_traits>
template <class value_t,
typename std::enable_if<std::is_floating_point<value_t>::value,
int>::type = 0>
struct Calculator {
Calculator() = default;
explicit operator bool() {
while (true) {
std::cout << "Valid operations: +, -, *, /, 0 (exit)\n";
std::cout << "What would you like to do: ";
if (!getUserInput(operation)) {
std::cerr << "Wrong input for operation\n";
continue;
}
switch (operation) {
case '0':
return false;
case '+':
case '-':
case '*':
case '/':
break;
default:
std::cerr << "Wrong input for operation\n";
continue;
}
std::cout << "Please enter v1: ";
if (!getUserInput(v1)) {
std::cerr << "Wrong input for v1\n";
continue;
}
std::cout << "Please enter v2: ";
if (!getUserInput(v2)) {
std::cerr << "Wrong input for v2\n";
continue;
}
calculate();
return true;
}
}
friend std::ostream &operator<<(std::ostream &os, const Calculator &c) {
os << "v1 " << c.operation << " v2 = " << c.result;
return os;
}
private:
char operation;
value_t v1, v2, result;
std::string line;
void calculate() {
switch (operation) {
case '+':
return calculate(std::plus<value_t>{});
case '-':
return calculate(std::minus<value_t>{});
case '*':
return calculate(std::multiplies<value_t>{});
case '/':
return calculate(std::divides<value_t>{});
case '0':
return;
}
}
template <class Func> void calculate(Func &&f) { result = f(v1, v2); }
template <class T> bool getUserInput(T &t) {
std::cin >> line;
std::istringstream ss{line};
return (ss >> t) && (ss >> std::ws).eof();
}
};
int main() {
Calculator<double> c;
while (c)
std::cout << c << '\n';
return 0;
}