I've written an C++ program to check if an string expression enter by the user is balanced eg: (2+(2)).

My program runs and checks for input such as {} however does not return the correct value when input such as {a} are entered.

This is my code, I can't seem to find the issue with my algorithm.

HEADER FILE

#ifndef BALANCED_H #define BALANCED_H

#include

class Balanced { public: Balanced(std::string); bool isBalanced(); bool isMatch(char c, char d);

private: std::string expression; };

#endif // BALANCED_H

IMPLEMENTATION FILE

#include "Balanced.h" #include #include #include

Balanced::Balanced(std::string s) : expression(s) { }

bool Balanced::isBalanced() { std::stack b;

for(unsigned int i=0; i < expression.size(); i++) { if(expression[i]=='{'|| expression[i] == '[' || expression[i] == '(') { b.push(expression[i]); continue; }

if(b.empty() || !isMatch(b.top(), expression[i])) { return false; }

else{ b.pop(); } } return b.empty();

}

bool Balanced::isMatch(char c, char d) { if(c == '{' && d == '}') { return true; } else if(c == '[' && d == ']') { return true; }

else if(c == '(' && d == ')') { return true; }

else { return false; } }

MAIN

#include #include "Balanced.h" #include

void displayHelp();

int main() { std::string s; std::string expression;

std::cout<<"Welcome to balance expression program" <

do{ std::cout<<"Enter any key to continue or type 'Help' to display a help menu "; std::cout<<"You may also type 'Exit' to exit the program: ";

std::cin>>s;

if(s=="Help") { displayHelp(); continue; }

else if(s=="Exit") { break; }

else{ std::cout<<"Enter an expression: "; std::cin>>expression; } Balanced d(expression);

if(d.isBalanced()!=true){ std::cout<<"The expressions is not balanced"; std::cout<

else{ std::cout<<"The expression is balanced"; std::cout<

}while(s!="Exit");

return 0;

}

void displayHelp() { std::cout<

#include #include "Balanced.h" #include

void displayHelp();

int main() { std::string s; std::string expression;

std::cout<<"Welcome to balance expression program" <

do{ std::cout<<"Enter any key to continue or type 'Help' to display a help menu "; std::cout<<"You may also type 'Exit' to exit the program: ";

std::cin>>s;

if(s=="Help") { displayHelp(); continue; }

else if(s=="Exit") { break; }

else{ std::cout<<"Enter an expression: "; std::cin>>expression; } Balanced d(expression);

if(d.isBalanced()!=true){ std::cout<<"The expressions is not balanced"; std::cout<

else{ std::cout<<"The expression is balanced"; std::cout<

}while(s!="Exit");

return 0;

}

void displayHelp() { std::cout<