linux C++获取cpu使用率、内存使用率

在Linux系统中，获取CPU使用率和内存使用率可以通过读取/proc/stat和/proc/meminfo文件来实现。下面是Linux平台下获取CPU使用率和内存使用率的示例代码：

获取CPU使用率：

#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <unistd.h>

using namespace std;

double getCpuUsage() {
    static unsigned long long lastTotalUser, lastTotalUserLow, lastTotalSys, lastTotalIdle;
    ifstream fileStat("/proc/stat");
    string line;
    getline(fileStat, line);
    istringstream ss(line);
    ss.ignore(5); // skip "cpu" word

    unsigned long long totalUser, totalUserLow, totalSys, totalIdle, totalIOwait, totalIRQ, totalSoftIRQ;
    ss >> totalUser >> totalUserLow >> totalSys >> totalIdle >> totalIOwait >> totalIRQ >> totalSoftIRQ;

    if (totalUser < lastTotalUser || totalUserLow < lastTotalUserLow || totalSys < lastTotalSys || totalIdle < lastTotalIdle) {
        // Overflow detection. Just skip this value.
        return -1.0;
    }

    unsigned long long total = totalUser - lastTotalUser + totalUserLow - lastTotalUserLow + totalSys - lastTotalSys;
    double cpuUsage = total;
    total += totalIdle - lastTotalIdle;
    cpuUsage /= total;

    lastTotalUser = totalUser;
    lastTotalUserLow = totalUserLow;
    lastTotalSys = totalSys;
    lastTotalIdle = totalIdle;

    return cpuUsage * 100.0;
}

int main() {
    while (true) {
        double cpuUsage = getCpuUsage();
        cout << "CPU usage: " << cpuUsage << "%" << endl;
        usleep(1000000);
    }
    return 0;
}

获取内存使用率：

#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <unistd.h>

using namespace std;

double getMemoryUsage() {
    ifstream fileMem("/proc/meminfo");
    string line;
    getline(fileMem, line);
    istringstream ss(line);
    ss.ignore(256, ' ');
    unsigned long long totalMem;
    ss >> totalMem;
    totalMem *= 1024; // convert to bytes

    getline(fileMem, line);
    ss.str(line);
    ss.clear();
    ss.ignore(256, ' ');
    unsigned long long freeMem;
    ss >> freeMem;
    freeMem *= 1024;

    double memoryUsage = 100.0 * (totalMem - freeMem) / totalMem;

    return memoryUsage;
}

int main() {
    while (true) {
        double memoryUsage = getMemoryUsage();
        cout << "Memory usage: " << memoryUsage << "%" << endl;
        usleep(1000000);
    }
    return 0;
}

以上示例代码只是提供了一个简单的思路，实际应用中还需要对获取到的数据进行处理和显示。另外，Linux系统提供了更为底层的API函数，如getrusage()和sysinfo()等，也可以用于获取系统资源使用情况。