C++如何在`cout`中使用相对误差？

#include <iostream>
#include <cmath>

int main() {
    double trueValue = 3.14159;
    double approximateValue = 3.14;
    
    double relativeError = std::abs((trueValue - approximateValue) / trueValue);
    
    std::cout << "Approximate value: " << approximateValue << std::endl;
    std::cout << "True value: " << trueValue << std::endl;
    std::cout << "Relative error: " << relativeError << std::endl;
    
    return 0;
}