用c语言写有理数的四则运算

可以使用结构体来表示有理数，结构体包含分子和分母两个成员变量。四则运算可以通过分别对分子和分母进行加、减、乘、除的操作来实现。具体实现可以参考以下代码：

#include <stdio.h>

typedef struct {
    int numerator;  // 分子
    int denominator;  // 分母
} Rational;

// 求最大公约数
int gcd(int a, int b) {
    return b ==  ? a : gcd(b, a % b);
}

// 化简有理数
void simplify(Rational *r) {
    int g = gcd(r->numerator, r->denominator);
    r->numerator /= g;
    r->denominator /= g;
}

// 加法
Rational add(Rational a, Rational b) {
    Rational r;
    r.numerator = a.numerator * b.denominator + b.numerator * a.denominator;
    r.denominator = a.denominator * b.denominator;
    simplify(&r);
    return r;
}

// 减法
Rational sub(Rational a, Rational b) {
    Rational r;
    r.numerator = a.numerator * b.denominator - b.numerator * a.denominator;
    r.denominator = a.denominator * b.denominator;
    simplify(&r);
    return r;
}

// 乘法
Rational mul(Rational a, Rational b) {
    Rational r;
    r.numerator = a.numerator * b.numerator;
    r.denominator = a.denominator * b.denominator;
    simplify(&r);
    return r;
}

// 除法
Rational div(Rational a, Rational b) {
    Rational r;
    r.numerator = a.numerator * b.denominator;
    r.denominator = a.denominator * b.numerator;
    simplify(&r);
    return r;
}

int main() {
    Rational a = {1, 2};
    Rational b = {3, 4};

    Rational c = add(a, b);
    printf("%d/%d + %d/%d = %d/%d\n", a.numerator, a.denominator, b.numerator, b.denominator, c.numerator, c.denominator);

    Rational d = sub(a, b);
    printf("%d/%d - %d/%d = %d/%d\n", a.numerator, a.denominator, b.numerator, b.denominator, d.numerator, d.denominator);

    Rational e = mul(a, b);
    printf("%d/%d * %d/%d = %d/%d\n", a.numerator, a.denominator, b.numerator, b.denominator, e.numerator, e.denominator);

    Rational f = div(a, b);
    printf("%d/%d / %d/%d = %d/%d\n", a.numerator, a.denominator, b.numerator, b.denominator, f.numerator, f.denominator);

    return ;
}