Write a pseudocode function that uses a stack to determine w

Write a pseudocode function that uses a stack to determine whether a string is in the language L, where
L = {s : s contains equal numbers of A’s and B’s}.Using STL stack class, implement in C++ the pseudocode function and Write a main() program to test the function.

Solution

/*

Write a pseudocode function that uses a stack to determine whether a string is in the language L, where
L = {s : s contains equal numbers of A’s and B’s}.Using STL stack class, implement in C++ the pseudocode function and Write a main() program to test the function.

*/

/*psudo code

function whether_string_is_in_L(str){
  
   initialize a stack

   iterate over all the char of the string
       if char is \'a\' or \'b\' {
           if the stack is empty and
               push \'a\' or \'b\'
           else
               last = peek top of stack
               if last == current char{
                   push current char in stack
               }else{
                   pop from the stack
               }
       }

   if at the end, the length of stack is 0 i.e stack is empty ,
       the string belongs to L
   otherwise not
}

*/

#include <iostream> // std::cout
#include <stack> // std::stack
#include <vector> // std::vector
#include <deque> // std::deque
using namespace std;
#include <string>

int whether_string_is_in_L(string s){
   stack<char> mystack;

   for (int i = 0; i < s.length(); ++i)
   {
      if(s[i] == \'a\' || s[i] == \'b\'){

          if( mystack.empty() ) mystack.push(s[i]);
          else{

              if(s[i] == mystack.top()){
                  mystack.push(s[i]);
              }else{
                  mystack.pop();
              }
          }
      }
   }

   if(mystack.empty()){
      cout << \"string \" << s << \" belongs to family L\" << endl;
   }else{
      cout << \"string \" << s << \" does not belongs to family L\" << endl;
   }

   return 1;

}

int main ()
{
  

string s = \"aabssssaawss\";

whether_string_is_in_L(s);

s = \"a\";

whether_string_is_in_L(s);

s = \"b\";

whether_string_is_in_L(s);

s = \"ab\";

whether_string_is_in_L(s);

s = \"ababab\";

whether_string_is_in_L(s);

s = \"ababaaaa\";

whether_string_is_in_L(s);

return 0;
}