c语言 小数化为分数

以下是两种C语言将小数转换为分数的算法：

1. 使用辗转相除法[^1]

#include <stdio.h>

int gcd(int a, int b) {
    if (b == 0) {
        return a;
    }
    return gcd(b, a % b);
}

void decimalToFraction(double decimal) {
    int numerator = decimal * 1000000; // 将小数转换为整数
    int denominator = 1000000;
    
    int commonDivisor = gcd(numerator, denominator); // 求最大公约数
    numerator /= commonDivisor; // 分子除以最大公约数
    denominator /= commonDivisor; // 分母除以最大公约数
    
    printf("Fraction: %d/%d\n", numerator, denominator);
}

int main() {
    double decimal = 0.75;
    decimalToFraction(decimal); // 输出：Fraction: 3/4
    
    return 0;
}

2. 使用C++中的类

#include <iostream>
#include <string>
#include <cmath>

class Fraction {
private:
    int numerator;
    int denominator;
    
public:
    Fraction(double decimal) {
        int power = 0;
        while (decimal * pow(10, power) != round(decimal * pow(10, power))) {
            power++;
        }
        
        numerator = decimal * pow(10, power);
        denominator = pow(10, power);
        
        int commonDivisor = gcd(numerator, denominator);
        numerator /= commonDivisor;
        denominator /= commonDivisor;
    }
    
    int gcd(int a, int b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }
    
    void printFraction() {
        std::cout << "Fraction: " << numerator << "/" << denominator << std::endl;
    }
};

int main() {
    double decimal = 0.75;
    Fraction fraction(decimal);
    fraction.printFraction(); // 输出：Fraction: 3/4
    
    return 0;
}