C++:
数字取整

#include <iostream>
#include <cmath> // 用于四舍五入的函数

int main() {
    double num = 3.14;

    std::cout << "floor: " << std::floor(num) << "\n"; // 输出: floor: 3
    std::cout << "ceil: " << std::ceil(num) << "\n";   // 输出: ceil: 4
    std::cout << "round: " << std::round(num) << "\n"; // 输出: round: 3

    // 对于固定精度的四舍五入，例如四舍五入到两位小数：
    double precise_num = 3.146;
    double multiplier = 100.0;
    double rounded = std::round(precise_num * multiplier) / multiplier;

    std::cout << "四舍五入到两位小数: " << rounded << "\n"; // 输出: 四舍五入到两位小数: 3.15

    return 0;
}