Question

My output is not working correctly its telling me things aren't balanced when it should be telling me they are balanced. I cannot figure out where I went wrong.

here is the input.txt:

{{[a]b}[]([c])}
[]}b[]([])(}[
[][[{a}{b}{c}]]
({{[x]}([[[[[a]]]b]])c}[])
{{{{{{{{{a}}}}}}}}
{[}]
[[}[abc]{]]
[{{}()()([])}[}]]
{a}{{[a[[{(a)}]]]}}
[[({a[]})b]{}[({c[]}d)]]

#include <iostream>

#include <stack>

#include <fstream>

#include <string>

using namespace std;

bool isbalanced(string exp) {

   stack<char> mystack;

   char x;

   for (int i = 0;i < exp.length(); i++)

   {

   if (exp[i] == '(' || exp[i] == '{' || exp[i] == '[') {

   mystack.push(exp[i]);

   }

   if (mystack.empty())

   return false;

   switch (exp[i]) {

   case ')':

   x = mystack.top();

   mystack.pop();

   if (x == '{' || x == '[')

   return false;

   break;

   case '}':

   x = mystack.top();

   mystack.pop();

   if (x == '(' || x == '[')

   return false;

   break;

   case ']':

   x = mystack.top();

   mystack.pop();

   if (x == '(' || x == '{')

   return false;

   break;

   }

   }

   return (mystack.empty());

}

int main() {

ifstream inputfile;

   string exp;

  

inputfile.open("input.txt");

   while (getline(inputfile, exp)) {

   if (isbalanced(exp)) {

   cout<<exp<<"the expression is balanced. \n";

   }

   else{

   cout<<exp<<"the expression is not balanced. \n";

   }

}

return 0;

}

Answer 1

C++ code

#include <iostream>

#include <stack>

#include <fstream>

#include <string>

using namespace std;

bool isbalanced(string exp) {

   stack<char> mystack;

   char x;

   for (int i = 0;i < exp.length(); i++)

   {

   if (exp[i] == '(' || exp[i] == '{' || exp[i] == '[') {

   mystack.push(exp[i]);
   continue;

   }

   if (mystack.empty())

   return false;

   switch (exp[i]) {

   case ')':

   x = mystack.top();

   mystack.pop();

   if (x == '{' || x == '[')

   return false;

   break;

   case '}':

   x = mystack.top();

   mystack.pop();

   if (x == '(' || x == '[')

   return false;

   break;

   case ']':

   x = mystack.top();

   mystack.pop();

   if (x == '(' || x == '{')

   return false;

   break;

   }

   }

   return (mystack.empty());

}

int main() {

ifstream inputfile;

   string exp;

inputfile.open("input.txt");

   while (getline(inputfile, exp)) {

   if (isbalanced(exp)) {

   cout<<exp<<"the expression is balanced. \n";

   }

   else{

   cout<<exp<<"the expression is not balanced. \n";

   }

}

return 0;

}

sample output