pat basic 1034 有理数四则运算

本题要求编写程序，计算 2 个有理数的和、差、积、商。

输入格式：

输入在一行中按照 a1/b1 a2/b2 的格式给出两个分数形式的有理数，其中分子和分母全是整型范围内的整数，负号只可能出现在分子前，分母不为 0。

输出格式：

分别在 4 行中按照 有理数1 运算符 有理数2 = 结果 的格式顺序输出 2 个有理数的和、差、积、商。注意输出的每个有理数必须是该有理数的最简形式 k a/b，其中 k 是整数部分，a/b 是最简分数部分；若为负数，则须加括号；若除法分母为 0，则输出 Inf。题目保证正确的输出中没有超过整型范围的整数。

样例-1：">样例-1：">样例-1：">输入样例 1：

2/3 -4/2

输出样例 1：

2/3 + (-2) = (-1 1/3)
2/3 - (-2) = 2 2/3
2/3 * (-2) = (-1 1/3)
2/3 / (-2) = (-1/3)

输入样例 2：

5/3 0/6

输出样例 2：

1 2/3 + 0 = 1 2/3
1 2/3 - 0 = 1 2/3
1 2/3 * 0 = 0
1 2/3 / 0 = Inf

解题思路：

这道题做得想打人，这个输出格式太让人难受了

#include <stdio.h>

long long gcd(long long a, long long b)
{
	if ( a<0 ) a = -a;
	if ( b<0 ) b = -b;
	if ( a==0 || b==0 ) return 1;
	return ( b%a==0 ? a : gcd(b%a, a) );
}

int main(int argc, const char *argv[])
{
	long long a1, b1, a2, b2, resint, resfenzi, resfenmu;
	long long int1, fenzi1, fenmu1, int2, fenzi2, fenmu2, divisor, divisor1, divisor2;
	if ( scanf("%lld/%lld %lld/%lld", &a1, &b1, &a2, &b2)==EOF ) printf("error\n");
	int i;
	char oper[] = {'+','-','*','/'};
	
	int1 = a1/b1;
	fenzi1 = a1%b1;
	fenmu1 = b1;
	int2 = a2/b2;
	fenzi2 = a2%b2;
	fenmu2 = b2;
	divisor1 = gcd(fenzi1, fenmu1);
	divisor2 = gcd(fenzi2, fenmu2);
	fenzi1 /= divisor1;
	fenzi2 /= divisor2;
	fenmu1 /= divisor1;
	fenmu2 /= divisor2;
	
	for ( i=0; i<4; i++ ) {
		if ( int1<0 ) {
			fenzi1==0 ? printf("(%lld)", int1) : printf("(%lld %lld/%lld)", int1, -fenzi1, fenmu1) ;
		} else if ( int1==0 ) {
			if ( fenzi1<0 ) {
				printf("(%lld/%lld)", fenzi1, fenmu1);
			} else if ( fenzi1==0 ) {
				printf("0");
			} else {
				printf("%lld/%lld", fenzi1, fenmu1);
			}
		} else {
			fenzi1==0 ? printf("%lld", int1) : printf("%lld %lld/%lld", int1, fenzi1, fenmu1) ;
		}
		printf(" %c ", oper[i]);
		
		if ( int2<0 ) {
			fenzi2==0 ? printf("(%lld)", int2) : printf("(%lld %lld/%lld)", int2, -fenzi2, fenmu2) ;
		} else if ( int2==0 ) {
			if ( fenzi2<0 ) {
				printf("(%lld/%lld)", fenzi2, fenmu2);
			} else if ( fenzi2==0 ) {
				printf("0");
			} else {
				printf("%lld/%lld", fenzi2, fenmu2);
			}
		} else {
			fenzi2==0 ? printf("%lld", int2) : printf("%lld %lld/%lld", int2, fenzi2, fenmu2) ;
		}
		printf(" = ");
		
		switch ( i ) {
			case 0:
				resint = (a1*b2 + a2*b1)/(b1*b2);
				resfenzi = (a1*b2 + a2*b1)%(b1*b2);
				resfenmu = b1 * b2;
				divisor = gcd(resfenzi, resfenmu);
				resfenzi /= divisor;
				resfenmu /= divisor;
				break;
			case 1:
				resint = (a1*b2 - a2*b1)/(b1*b2);
				resfenzi = (a1*b2 - a2*b1)%(b1*b2);
				resfenmu = b1 * b2;
				divisor = gcd(resfenzi, resfenmu);
				resfenzi /= divisor;
				resfenmu /= divisor;
				break;
			case 2:
				resint = (a1*a2)/(b1*b2);
				resfenzi = (a1*a2)%(b1*b2);
				resfenmu = b1 * b2;
				divisor = gcd(resfenzi, resfenmu);
				resfenzi /= divisor;
				resfenmu /= divisor;
				break;
			case 3:
				if ( a2!=0 ) {
					resint = (a1*b2)/(a2*b1);
					resfenzi = (a1*b2)%(a2*b1);
					resfenmu = a2 * b1;
					divisor = gcd(resfenzi, resfenmu);
					resfenzi /= divisor;
					resfenmu /= divisor;
					if ( resfenzi<0 ) resfenzi = -resfenzi;
					if ( resfenmu<0 ) resfenmu = -resfenmu;
					int sign = 1;
					if ( a1*a2<0 ) sign = -1;
					resfenzi *= sign;
					
					if ( resint<0 ) {
						resfenzi==0 ? printf("(%lld)\n", resint) : printf("(%lld %lld/%lld)\n", resint, -resfenzi, resfenmu) ;
					} else if ( resint==0 ) {
						if ( resfenzi<0 ) {
							printf("(%lld/%lld)\n", resfenzi, resfenmu);
						} else if ( resfenzi==0 ) {
							printf("0\n");
						} else {
							printf("%lld/%lld\n", resfenzi, resfenmu);
						}
					} else {
						resfenzi==0 ? printf("%lld\n", resint) : printf("%lld %lld/%lld\n", resint, resfenzi, resfenmu) ;
					}
				} else {
					printf("Inf\n");
				}
		}
		if ( i<3 ) {
			if ( resint<0 ) {
				resfenzi==0 ? printf("(%lld)\n", resint) : printf("(%lld %lld/%lld)\n", resint, -resfenzi, resfenmu) ;
			} else if ( resint==0 ) {
				if ( resfenzi<0 ) {
					printf("(%lld/%lld)\n", resfenzi, resfenmu);
				} else if ( resfenzi==0 ) {
					printf("0\n");
				} else {
					printf("%lld/%lld\n", resfenzi, resfenmu);
				}
			} else {
				resfenzi==0 ? printf("%lld\n", resint) : printf("%lld %lld/%lld\n", resint, resfenzi, resfenmu) ;
			}
		}
	}
	
	return 0;
}