Dequeue a char from an inserted string entry in queue

Question

I have a queue where I happen to push a string on it as my first entry and then I want to dequeue each char of that string individually, I tried two approaches:

   string s ="()()h)"
    queue<string> q;
    q.push(s);        
    while(!q.empty())
    {
        string temp = q.front();
        q.pop();
}

That results on popping the string as a whole, I have also tried converting the string to an array of char, like this:

    string input ="()()h)"
    char s[input.size() + 1];
    strcpy(s,input.c_str());

Help would be appreciated, thank you.

Answer 1

It seems you want to create a queue of characters. In this case the queue definition can look like it is shown in the demonstrative program below.

#include <iostream>
#include <string>
#include <queue>

int main() 
{
    std::string s = "()()h)";
    std::queue<char> q( std::queue<char>::container_type( s.begin(), s.end() ) );

    while ( not q.empty() )
    {
        char c = q.front();
        q.pop();
        std::cout << c;
    }

    std::cout << '\n';

    return 0;
}

The program output is

()()h)

To push a string in an already existent queue you can use for example the standard algorithm std::for_each (or the range-based for loop).

#include <iostream>
#include <string>
#include <queue>
#include <iterator>
#include <algorithm>

int main() 
{
    std::string s = "()()h)";
    std::queue<char> q;

    std::for_each( std::begin( s ), std::end( s ), 
                   [&q]( const auto &item )
                   {
                        q.emplace( item );
                   } );

    while ( not q.empty() )
    {
        char c = q.front();
        q.pop();
        std::cout << c;
    }

    std::cout << '\n';

    return 0;
}