Question

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c++ sort with structs

I am trying to figure out how to sort an array of structs on a specific variable in the struct held within the array. Here is my code:

struct Process{
    int pid;
    int burst;
    int arrival;
};

int main(int argc, char *argv[]){

    // The number of processes
    int numProcesses = 3;

    //Create an array that holds 10 Process structs
    Process *arrayOfProcesses = new Process[numProcesses];

    // Puts values in each pid, burst, and arrival
    arrayOfProcesses[0].pid = 0;
    arrayOfProcesses[0].burst = 8;
    arrayOfProcesses[0].arrival = 2;

    arrayOfProcesses[1].pid = 1;
    arrayOfProcesses[1].burst = 12;
    arrayOfProcesses[1].arrival = 3;

    arrayOfProcesses[2].pid = 2;
    arrayOfProcesses[2].burst = 4;
    arrayOfProcesses[2].arrival = 1;

    // Sort the array based on the arrival time
    // Help! :)
}

I would really like to be able to sort the array in my code on the arrival time. I’ve simplified my code to give you a general idea of what I’m trying to accomplish. In my actual code,t he array is filled dynamically from information read in by a file. I know that using a List or even a Vector would be better options, but I am determined to figure this out using arrays.

Any help with sorting this would be appreciated! 🙂

Answer 1

Use sort from the standard <algorithm> header:

std::sort(arrayOfProcesses, arrayOfProcesses+numProcesses, [](Process const &a, Process const &b){ return a.arrival < b.arrival; });