（算法练习）——分数的一些计算

《算法笔记》P158
把分数的加减乘除敲了一遍，算是熟悉下结构体

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <algorithm>
using namespace std;

//求最大公约数的代码 
int gcd(int a,int b){
	if(b == 0) return a;
	else return gcd(b,a%b);
}
//定义分数的结构体 
struct Fraction{
	int up,down;
};

//分数化简
Fraction reduction(Fraction result){
	if(result.down <0){
		result.up = -result.up;
		result.down = -result.down;
	}
	if(result.up == 0){
		result.down = 1;
	}
	else{
		int d = gcd(abs(result.up),abs(result.down));
		result.up /= d;
		result.down /= d;
	}
	
	return result;
}
//分数的加法 
Fraction add(Fraction f1,Fraction f2){
	Fraction result;
	result.up = f1.up * f2.down + f2.up*f1.down;
	result.down = f1.down * f2.down;
	return reduction(result);
}

//分数的减法 
Fraction mius(Fraction f1,Fraction f2){
	Fraction result;
	result.up = f1.up*f2.down - f2.up * f1.down;
	result.down = f1.down*f2.down;
	return reduction(result);
}

//分数的乘法
Fraction multi(Fraction f1,Fraction f2){
	Fraction result;
	result.up = f1.up*f2.up;
	result.down = f1.down * f2.down;
	return reduction(result);
} 
//分数的除法
Fraction divide(Fraction f1,Fraction f2){
	Fraction result;
	result.up = f1.up*f2.down;
	result.down = f1.down*f2.up;
	return reduction(result);
} 
//分数的输出 
void showResult(Fraction r){
	r = reduction(r);
	if(r.down == 1) printf("%d",r.up);
	else if(abs(r.up) > r.down){
		printf("%d %d/%d",r.up/r.down,abs(r.up)%r.down,r.down);
	}
	else{
		printf("%d/%d",r.up,r.down);
	}
}

int main(){
	struct Fraction aa;
	aa.down = 25;
	aa.up = 20;
	//此处如果直接 printf("%d/%d",aa.up,aa.down);则是化简之前的数据 
	printf("%d/%d\n",reduction(aa).up,reduction(aa).down);
	showResult(aa);
}