Question

我正在创建一个cpu调度程序，一旦readInput函数返回，我就会遇到分段错误。根据我的阅读，堆栈会以某种方式被破坏。

我已经确定了导致它的代码行，但我无法弄清楚原因。

以下是流程类的相关部分：

class Process{      //Process class deals with the values of various variables the process will take on over the course of execution on a process
public:

Process(){
    pid = startTime = endTime = initPriority = priority = timeSlice = totalCpuBurst = totalCpuTime = totalIoTime = 0;
}

void setPid(int proId){pid = proId;}

void setPriority(int bonus){priority = initPriority + bonus;}

void setProcessStart(int start){startTime = start;}

void setTimeSlice(int t){timeSlice = t;}

void setInitPriority(int nice){
    initPriority = (int)(((nice + 20)/39.0)*30 + 0.5) + 105;
}

void setNumCpuBurst(int duration){numCpuBurst.push_back(duration);}

void setNumIoBurst(int duration){numIoBurst.push_back(duration);}

private:
int pid, startTime, endTime, initPriority, priority, timeSlice, totalCpuBurst, totalCpuTime, totalIoTime;
vector<int> numCpuBurst;
vector<int>numIoBurst;
};

这是readInput函数。 Cin在运行程序时来自文件间接。该文件包含4行或更多的整数，每行由＆＃34; ***＆＃34;在文件的末尾。目前我的测试文件中只有3个进程

void readInput(Process process[], int &processCount){           //read the input from the file until "***" is encountered
vector<int> values;
string inLine;
int n;
getline(cin, inLine);

while(inLine.compare("***")){
    stringstream stream(inLine);
    while(stream >> n){
        values.push_back(n);
    }

    for(int i = 0; i< values.size(); i++){
        if(i == 0){                                               //get nice value, set pid and priority
            process[processCount].setPid(processCount);
            process[processCount].setInitPriority(values[i]);
            process[processCount].setPriority(0);
        }
        else if(i == 1){                                           //arrival time
            process[processCount].setProcessStart(values[i]);
        }
        else if(i == 2){                                           //number of cpu bursts
            process[processCount].setTotalCpuBurst(values[i]);
        }
        else if(i >= 3){
            if(i % 2 == 1){                                         //CPU burst
                process[processCount].setNumCpuBurst(values[i]);
            }
            else{                                                   //IO burst
                process[processCount].setNumIoBurst(values[i]);
            }
        }
    }
values.clear();
getline(cin, inLine);
processCount++;
}

    cout << "break on return";
    return;
}

＆＃34;在返回时休息＆＃34;打印然后我收到分段错误

这是导致分段错误的块

        else if(i == 1){                                           //arrival time
            process[processCount].setProcessStart(values[i]);
        }

这是到目前为止的主要功能

int main() {
    vector<Process> active, expired, io, finished, cpu;
    Process startUp[4];
    int processCount = 0, runningCount = 0;
    readInput(startUp, processCount);
    cout << "\nafter read";
    return 0;
}

Answer 1

您可以Process超过4个，但只分配4个Process的数组

对于超过4的所有值，这将崩溃

process[processCount].setProcessStart(values[i]);

尝试更改为以下

#define MAX_PROCESS  80
Process startUp[MAX_PROCESS];

MAX_PROCESS是您的文件可以拥有的最大进程数

根据您之前的回答，似乎4就是您的问题，但根据您的意见，并非如此，我建议您使用backtrace更新问题。

函数返回C ++的分段错误

1 个答案: