please help

[4y64izwU]

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[Smac89]

queue<int> pid;
if (input == 'A'){
    pid.push(0);
    ....

[4y64izwU]

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[4y64izwU]

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[4y64izwU]

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[Smac89]

Look at the if-statement in my code and look at yours then look at mine and back to yours, what do you see? You see a single `=` sign in yours and notice the `==` in mine. Why does yours not look like mine? I don't know. Now back to yours, change it to look like mine and run your code, what happens now?

[4y64izwU]

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[Smac89]

Paste your new program here and we will see what the problem is

[4y64izwU]

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[4y64izwU]

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[JLBorges]

#include <iostream>

int main ()
{
    int qfront = 0 ;
    int qback = 0 ;

    char c ;
    while( std::cin >> c )
    {
        switch(c)
        {
            case 'A':
            case 'a':
                std::cout << "A process with PID " << ++qback << " has arrived!\n" ;
                break ;

            case 'T':
            case 't':
                if( qfront < qback ) std::cout << "A process with PID " << ++qfront << " has died!\n" ;
                break ;

            case '?':
                if( qfront == qback ) std::cout << "no processes are alive.\n" ;
                else if( qfront == (qback-1) ) std::cout << "processes with PID " << qback << " is alive.\n" ;
                else std::cout << "processes with PIDs " << qfront+1 << " to "  << qback << " are alive.\n" ;
                break ;

            case 'Q':
            case 'q':
                return 0 ;

            default:
                std::cout << "invalid input.\n" ;

        }
    }
}

[4y64izwU]

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[Smac89]

This means that you need a stack rather than a queue. A queue will kill the processes in the order they arrived, and a stack will do it in reverse. Also have you tried what JLBorges suggested?

[4y64izwU]

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