#include <stdio.h>

#define N   4   // Process count

typedef struct{
    char pid[3];    //Process name
    int bt;         //CPU Burst time
    int rt;         //Remaining time
    int ct;         //Completion time
    int tat;        //Turnaround time
    int wt;         //Waiting time
} Process;

int main(){
    Process p[N] = {
        {"P1", 6, 6, 0, 0, 0},
        {"P2", 3, 3, 0, 0, 0},
        {"P3", 1, 1, 0, 0, 0},
        {"P4", 7, 7, 0, 0, 0}
    };

    int q;  //Time quantum
    int cs; //Context switch time
    printf("규정 시간량 입력 : ");
    scanf("%d", &q);
    printf("문맥 교환 시간 입력 : ");
    scanf("%d", &cs);

    int time = 0;
    int done = 0;

    printf("\n간트 차트 : \n");
    while(done < N){
        for(int i = 0; i < N; i++){
            if(p[i].rt > 0){
                int exec = (p[i].rt > q) ? q : p[i].rt;
                int start = time;

                time += exec;
                p[i].rt -= exec;

                if(p[i].rt == 0){
                    p[i].ct = time;
                    p[i].tat = p[i].ct;
                    p[i].wt = p[i].tat - p[i].bt;
                    done++;
                    printf("| %s (%d~%d 완료) ", p[i].pid, time - exec, time);
                }else{
                    printf("| %s (%d~%d, 남은 %d) ", p[i].pid, start, time, p[i].rt);
                }

                if(done < N){ 
                    printf("| CS (%d~%d) ", time, time + cs);
                    time += cs; 
                }
            }
        }
    }
    printf("|\n");

    printf("\nProcess\tBT\tCT\tTAT\tWT\n");
    int sumTAT = 0, sumWT = 0;
    for(int i = 0; i < N; i++){
        printf("%s\t%d\t%d\t%d\t%d\n", p[i].pid, p[i].bt, p[i].ct, p[i].tat, p[i].wt);
        sumTAT += p[i].tat;
        sumWT += p[i].wt;
    }

    printf("\n평균 반환시간 : %.2f\n", (float)sumTAT / N);
    printf("평균 대기시간 : %.2f\n", (float)sumWT / N);

    return 0;
}