c++ checking if braces match - c++

Question

I've been asked as a bonus programming challenge to see if braces match in a random string or char like this: {1+1} this would return 1, while {1+1}) would return 0.
This is what I have so far but it doesn't seem to do anything. Any help would be great? thanks
//bonus.cpp
#include <iostream>
#include <string>
#include <queue>
#include <stack>
using namespace std;
int checkBraces (string s)
{
//int myLength = s.length();
std::stack<int> stack;
char d;
for (int i = 0; i < s.length(); i++)
{
char c = s[i];
if (c == '(')
{
stack.push(c);
}
else if (c == '[')
{
stack.push(c);
}
else if (c == '{')
{
stack.push(c);
}
else if (c == ')')
{
if (stack.empty())
{
return false;
}
else
{
d = stack.top();
stack.pop();
if (d != '(')
{
return false;
}
}
}
else if (c == ']')
{
if (stack.empty())
{
return false;
}
else
{
d = stack.top();
stack.pop();
if (d != '[')
{
return false;
}
}
}
else if (c == '}')
{
if (stack.empty())
{
return false;
}
else
{
d = stack.top();
stack.pop();
if (d != '{')
{
return false;
}
}
}
}
if (stack.empty()) return true;
else return false;
}
int main()
{
cout << "This program checks brace ([{}]) matching in a string." << endl;
checkBraces ("{1+1}");
}

Answer 1

What makes you think it doesn't do anything? It does. It checks for braces, but you're not doing anything with the return of checkBraces, which, btw, should return a bool, not an int.
Did you perhaps meant something like:
if (checkBraces ("{1+1}"))
cout << "matching";
else
cout << "not matching";
Pro-tip: learn how to use a debugger. You should learn how to debug before you start coding anything more than a "hello world".

Answer 2

As an addition to what have already been said, I would say that you could reduce the amount of code. As anyway you put chars into your stack, why not having a std::stack<char>?
You could save the braces into another string, to automatically compare it using one of the std::algorithms
const std::string openingBraces("{[(");
const std::string closingBraces("}])");
if (std::find(openingBraces.begin(), openingBraces.end(), currentChar) != openingBraces.end())
yourStack.push(currentChar);
else if (std::find(closingBraces.begin(), closingBraces.end(), currentChar) != closingBraces.end())
{
// check if currentChar is matching the one on top of your stack
}
I haven't written everything as it's always better to find answers by yourself.

Answer 3

Minimum you should do is to print the outcome of checkBraces.

Answer 4

but it doesn't seem to do anything
It does do something. It prints This program checks brace ([{}]) matching in a string..
You are calling checkBraces ("{1+1}") but you aren't doing anything with the returned value. Since this call can be optimized away, you are in a sense correct that your program doesn't seem to do anything.
So make it do something. Print the string that is to be tested, then print the result of the test. Once you have done that, you should test, and when you're done with that, you should test some more. Don't just test easy cases such as {i+1}. Test convoluted cases that should pass, and also test cases that should fail.
Learning how to test and learning how to debug are just as important skills (if not more important skills) as is learning how to write code.