我正在尝试用c ++实现FCFS CPU调度。我有以下代码，它运行没有错误但是给了我一些数字的“垃圾数据”，例如等待时间的值，响应时间和所有过程的转换时间，除了第一个计算
#include "stdafx.h"
#include <iostream>
#include <string>
using namespace std;
class ProcessInfo
{
public:
string ProcessID;
int BurstTime;
int Arrival;
int WaitingTime;
int ResponseTime;
int TurnaroundTime;
};
int main()
{
ProcessInfo P1, P2, P3 = ProcessInfo();
ProcessInfo Array[3] = {P1, P2, P3};
for(int i = 0; i < 3; i++)
{
cout<<"Please enter Process ID for process "<<i<<endl;
cin>>Array[i].ProcessID;
cout<<"Please enter Burst Time for process "<<i<<endl;
cin>>Array[i].BurstTime;
cout<<"Please enter Arrival Time for process "<<i<<endl;
cin>>Array[i].Arrival;
}
if (Array[0].Arrival < Array[1].Arrival && Array[0].Arrival < Array[2].Arrival)
{
if (Array[1].Arrival < Array[2].Arrival)
{
P1.WaitingTime = 0;
P1.ResponseTime = 0;
P1.TurnaroundTime = P1.BurstTime;
P2.WaitingTime = P1.TurnaroundTime - (P2.Arrival - P1.Arrival);
P2.ResponseTime = 0;
P2.TurnaroundTime = P2.WaitingTime + P2.BurstTime;
P3.WaitingTime = P2.TurnaroundTime - (P3.Arrival - P2.Arrival);
P3.ResponseTime = P2.TurnaroundTime - (P3.Arrival - P2.Arrival) ;
P3.TurnaroundTime = P3.WaitingTime + P3.BurstTime;
cout<<"Order of processes is: P1, P2, P3"<<endl;
cout<<"The waiting time for P1: "<< P1.WaitingTime<<endl;
cout<<"The response time for P1: "<<P1.ResponseTime<<endl;
cout<<"The Turnaround time for P1: "<<P1.TurnaroundTime<<endl;
cout<<"The waiting time for P2: "<< P2.WaitingTime<<endl;
cout<<"The response time for P2: "<<P2.ResponseTime<<endl;
cout<<"The Turnaround time for P2: "<<P2.TurnaroundTime<<endl;
cout<<"The waiting time for P3: "<< P3.WaitingTime<<endl;
cout<<"The response time for P3: "<<P3.ResponseTime<<endl;
cout<<"The Turnaround time for P3: "<<P3.TurnaroundTime<<endl;
}
else
if (Array[2].Arrival < Array[1].Arrival)
{
P1.WaitingTime = 0;
P1.ResponseTime = 0;
P1.TurnaroundTime = P1.BurstTime;
P3.WaitingTime = P1.TurnaroundTime - (P3.Arrival - P1.Arrival);
P3.ResponseTime = P3.WaitingTime;
P3.TurnaroundTime = P3.WaitingTime + P3.BurstTime;
P2.WaitingTime = P3.TurnaroundTime - (P2.Arrival - P3.Arrival);
P2.ResponseTime = P2.WaitingTime;
P2.TurnaroundTime = P2.WaitingTime + P2.BurstTime;
cout<<"Order of processes is: P1, P3, P2"<<endl;
cout<<"The waiting time for P1: "<< P1.WaitingTime<<endl;
cout<<"The response time for P1: "<<P1.ResponseTime<<endl;
cout<<"The Turnaround time for P1: "<<P1.TurnaroundTime<<endl;
cout<<"The waiting time for P3: "<< P3.WaitingTime<<endl;
cout<<"The response time for P3: "<<P3.ResponseTime<<endl;
cout<<"The Turnaround time for P3: "<<P3.TurnaroundTime<<endl;
cout<<"The waiting time for P2: "<< P2.WaitingTime<<endl;
cout<<"The response time for P2: "<<P2.ResponseTime<<endl;
cout<<"The Turnaround time for P2: "<<P2.TurnaroundTime<<endl;
}
}
else
if(Array[1].Arrival < Array[0].Arrival && Array[1].Arrival < Array[2].Arrival)
{
if (Array[2].Arrival < Array[0].Arrival)
{
P2.WaitingTime = 0;
P2.ResponseTime = 0;
P2.TurnaroundTime = P2.BurstTime;
P3.WaitingTime = P2.TurnaroundTime - (P3.Arrival - P2.Arrival);
P3.ResponseTime = P3.WaitingTime;
P3.TurnaroundTime = P3.WaitingTime + P3.BurstTime;
P1.WaitingTime = P3.TurnaroundTime - (P1.Arrival - P3.Arrival);
P1.ResponseTime = P1.WaitingTime;
P1.TurnaroundTime = P1.WaitingTime + P1.BurstTime;
cout<<"Order of processes is: P2, P3, P1"<<endl;
cout<<"The waiting time for P2: "<< P2.WaitingTime<<endl;
cout<<"The response time for P2: "<<P2.ResponseTime<<endl;
cout<<"The Turnaround time for P2: "<<P2.TurnaroundTime<<endl;
cout<<"The waiting time for P3: "<< P3.WaitingTime<<endl;
cout<<"The response time for P3: "<<P3.ResponseTime<<endl;
cout<<"The Turnaround time for P3: "<<P3.TurnaroundTime<<endl;
cout<<"The waiting time for P1: "<< P1.WaitingTime<<endl;
cout<<"The response time for P1: "<<P1.ResponseTime<<endl;
cout<<"The Turnaround time for P1: "<<P1.TurnaroundTime<<endl;
}
else
if (Array[0].Arrival < Array[2].Arrival)
{
P2.WaitingTime = 0;
P2.ResponseTime = 0;
P2.TurnaroundTime = P2.BurstTime;
P1.WaitingTime = P2.TurnaroundTime - (P1.Arrival - P2.Arrival);
P1.ResponseTime = P1.WaitingTime;
P1.TurnaroundTime = P1.WaitingTime + P1.BurstTime;
P3.WaitingTime = P1.TurnaroundTime - (P3.Arrival - P1.Arrival);
P3.ResponseTime = P3.WaitingTime;
P3.TurnaroundTime = P3.WaitingTime + P3.BurstTime;
cout<<"Order of processes is: P2, P1, P3"<<endl;
cout<<"The waiting time for P2: "<< P2.WaitingTime<<endl;
cout<<"The response time for P2: "<<P2.ResponseTime<<endl;
cout<<"The Turnaround time for P2: "<<P2.TurnaroundTime<<endl;
cout<<"The waiting time for P1: "<< P1.WaitingTime<<endl;
cout<<"The response time for P1: "<<P1.ResponseTime<<endl;
cout<<"The Turnaround time for P1: "<<P1.TurnaroundTime<<endl;
cout<<"The waiting time for P3: "<< P3.WaitingTime<<endl;
cout<<"The response time for P3: "<<P3.ResponseTime<<endl;
cout<<"The Turnaround time for P3: "<<P3.TurnaroundTime<<endl;
}
}
else
if(Array[2].Arrival < Array[1].Arrival && Array[2].Arrival < Array[0].Arrival)
{
if (Array[1].Arrival < Array[0].Arrival)
{
P3.WaitingTime = 0;
P3.ResponseTime = 0;
P3.TurnaroundTime = P1.BurstTime;
P2.WaitingTime = P3.TurnaroundTime - (P2.Arrival - P3.Arrival);
P2.ResponseTime = P2.WaitingTime;
P2.TurnaroundTime = P2.WaitingTime + P2.BurstTime;
P1.WaitingTime = P2.TurnaroundTime - (P1.Arrival - P2.Arrival);
P1.ResponseTime = P1.WaitingTime;
P1.TurnaroundTime = P1.WaitingTime + P1.BurstTime;
cout<<"Order of processes is: P3, P2, P1"<<endl;
cout<<"The waiting time for P3: "<< P3.WaitingTime<<endl;
cout<<"The response time for P3: "<<P3.ResponseTime<<endl;
cout<<"The Turnaround time for P3: "<<P3.TurnaroundTime<<endl;
cout<<"The waiting time for P2: "<< P2.WaitingTime<<endl;
cout<<"The response time for P2: "<<P2.ResponseTime<<endl;
cout<<"The Turnaround time for P2: "<<P2.TurnaroundTime<<endl;
cout<<"The waiting time for P1: "<< P1.WaitingTime<<endl;
cout<<"The response time for P1: "<<P1.ResponseTime<<endl;
cout<<"The Turnaround time for P1: "<<P1.TurnaroundTime<<endl;
}
else
if (Array[0].Arrival < Array[1].Arrival)
{
P3.WaitingTime = 0;
P3.ResponseTime = 0;
P3.TurnaroundTime = P1.BurstTime;
P1.WaitingTime = P3.TurnaroundTime - (P1.Arrival - P3.Arrival);
P1.ResponseTime = P1.WaitingTime;
P1.TurnaroundTime = P1.WaitingTime + P1.BurstTime;
P2.WaitingTime = P1.TurnaroundTime - (P2.Arrival - P1.Arrival);
P2.ResponseTime = P2.WaitingTime;
P2.TurnaroundTime = P2.WaitingTime + P2.BurstTime;
cout<<"Order of processes is: P3, P1, P2"<<endl;
cout<<"The waiting time for P3: "<< P3.WaitingTime<<endl;
cout<<"The response time for P3: "<<P3.ResponseTime<<endl;
cout<<"The Turnaround time for P3: "<<P3.TurnaroundTime<<endl;
cout<<"The waiting time for P1: "<< P1.WaitingTime<<endl;
cout<<"The response time for P1: "<<P1.ResponseTime<<endl;
cout<<"The Turnaround time for P1: "<<P1.TurnaroundTime<<endl;
cout<<"The waiting time for P2: "<< P2.WaitingTime<<endl;
cout<<"The response time for P2: "<<P2.ResponseTime<<endl;
cout<<"The Turnaround time for P2: "<<P2.TurnaroundTime<<endl;
}
}
}
答案 0 :(得分：1)
您没有初始化变量P1和P2，因此这些结构的内容将是未定义的。
这将进行类似
的操作P1.TurnaroundTime = P1.BurstTime;
未定义。
如果您想要良好的起始值，请添加默认构造函数。
答案 1 :(得分：0)
请勿使用P1，P2和P3进行计算。而是使用Array[0]，Array[1]和Array[2]。
答案 2 :(得分：-3)
#include<iostream>
#include<cstdio>
#include<cstdlib>
int process,*q,i,slice,a=0,at2[10],to[10];
void takeprocess()
{
printf("Enter the total number of process\n");
scanf("%d",&process);
}
void takecputime()
{
q=(int*)calloc(process,(sizeof(int)));
for(i=1;i<=process;i++)
{
printf("Enter the CPU burst time for the process P%d : ",i);
scanf("%d",q+i);
to[i]=at2[i]=*(q+i);
}
}
void checkfcfs()
{
int wt1[process];
for(i=1;i<process;i++)
{
a=wt1[i]=*(q+i)+a;
}
a=0;
printf("the waiting time for process P1 is : 0\n");
for(i=1;i<process;i++)
{
a=wt1[i]+a;
printf("the waiting time for process P%d is : %d\n",i+1,wt1[i]);
}
a=a/process;
printf("the average waiting time for processes are :%d\n",a);
printf("the sequence of the processes are as follows\n");
for(i=1;i<=process;i++)
{
printf("P%d\n",i);
}
}
using namespace std;
int main()
{
takeprocess();
takecputime();
checkfcfs();
return 0;
}