寫一個程序，讓控制cpu利用率在20%左右
思路很簡單：每個循環控制sleep的時間占比

#include <iostream>
#include <chrono>
#include <unistd.h>int main() {int ratio = 20;int base_time = 1000;int sleeptime = base_time * (100-ratio);int runtime = base_time * ratio;while(true) {auto start = std::chrono::high_resolution_clock::now();while(std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::high_resolution_clock::now() - start).count() < runtime) {}usleep(sleeptime);}return 0;
}