分数四则运算

预备知识：
1、分数化简

第一种情况：如假分数17/2，最终需要化简成8 1/2；即a b/c的形式
其中a = 分子/分母； b = 分子%分母；c是分母
第二种情况：6/9，需要化简成2/3；即将分子分母同时除以最大公约数
求最大公约数算法如下：

/*a 和 b的最大公约数*/ int gcd(int a, int b){ 	if(b == 0) return a; 	else return gcd(b, a % b); 

一、加法运算（正数与正数相加）

/* 1、分数相加 2、约分 3、判断是否是假分数，化简 */ #include<stdio.h> int gcd(int a, int b) { 	if (b == 0) return a; 	else return gcd(b, a % b); } void addRationalNumber(int up1, int down1, int up2, int down2, int *up, int *down) { 	int temp; 	*down = down1 * down2; 	*up = up1 * down2 + up2 * down1; 	temp = gcd(*up, *down);		//temp保存最大公约数的值 	/*约分*/ 	*down /= temp; 	*up /= temp; } /*化简成a b/c的形式*/ void fenshu(int up, int down) { 	int a, b; 	a = up / down; 	b = up % down; 	printf("%d %d/%d", a, b, down); } int main(void) { 	int up1, down1, up2, down2; 	int up, down; 	scanf("%d/%d %d/%d", &up1, &down1, &up2, &down2); 	addRationalNumber(up1, down1, up2, down2, &up, &down); 	if (up > down)  		fenshu(up, down); 	else if(up < down) 		printf("%d/%d\n", up, down); 	else  		printf("1"); 	return 0; } 

文章来源: https://blog.csdn.net/qq_43417071/article/details/91491723