linux下C++获取CPU总使用率

你可以使用Linux下的/proc文件系统来获取CPU总使用率。其中，/proc/stat文件提供了当前系统的CPU使用情况，包括总CPU时间、空闲CPU时间、用户CPU时间、系统CPU时间等。你可以通过读取/proc/stat文件并解析其中的数据，计算出CPU的总使用率。

以下是获取CPU总使用率的C++代码示例：

#include <iostream>
#include <fstream>
#include <sstream>
#include <thread>
#include <chrono>

using namespace std;

double GetCPULoad()
{
    ifstream proc_stat("/proc/stat");
    string line;
    getline(proc_stat, line);
    istringstream iss(line);
    string cpu;
    long long user, nice, sys, idle, iowait, irq, softirq, steal, guest, guest_nice;
    iss >> cpu >> user >> nice >> sys >> idle >> iowait >> irq >> softirq >> steal >> guest >> guest_nice;
    long long PrevIdle = idle + iowait;
    long long PrevNonIdle = user + nice + sys + irq + softirq + steal;
    long long PrevTotal = PrevIdle + PrevNonIdle;

    this_thread::sleep_for(chrono::milliseconds(100)); // sleep for a short time to get the current CPU usage

    proc_stat.seekg(0);
    getline(proc_stat, line);
    istringstream iss2(line);
    iss2 >> cpu >> user >> nice >> sys >> idle >> iowait >> irq >> softirq >> steal >> guest >> guest_nice;
    long long Idle = idle + iowait;
    long long NonIdle = user + nice + sys + irq + softirq + steal;
    long long Total = Idle + NonIdle;

    // calculate CPU usage percentage
    double CPU_Percentage = (double)(Total - PrevTotal) / (double)(Total - PrevTotal + PrevIdle - Idle);
    return CPU_Percentage;
}

int main()
{
    // print CPU usage percentage every second
    while (true) {
        cout << "CPU usage: " << GetCPULoad() * 100 << "%" << endl;
        this_thread::sleep_for(chrono::seconds(1));
    }
    return 0;
}

该代码会每秒钟输出一次CPU使用率。你可以根据需要修改输出内容和时间间隔。