四则运算作业

| 这个作业属于哪个课程 | 计算机18级|
| ---- | ---- | ---- |
| 这个作业的要求在哪里 | 个人作业-四则运算题目生成程序（补做）|
| 这个作业的目标| 会编写四则运算代码|
| 学号 | 3180701212|

题目要求：*

写一个能自动生成小学四则运算题目的程序，然后在此基础上扩展：

除了整数以外，还要支持真分数的四则运算，例如：1/6+1/8=7/24
程序要求能处理用户的输入，判断对错，累积分数
程序支持可以由用户自行选择加、减、乘、除运算
使用-n参数控制生成题目的个数，例如Myapp.exe -n 10，将生成10个题目

主函数：
`int main(void)
{

struct fraction f = { 21, 3 };
struct fraction f1 = { 8, 64 };
struct fraction f2 = { 9, 711 };

struct fraction reducedf = reduce_fraction(f);
printf("%d/%d reduced to simplest terms: %d/%d\n", f.numerator,
    f.denominator, reducedf.numerator, reducedf.denominator);

struct fraction addedf = add_fractions(f1, f2);
printf("%d/%d + %d/%d = %d/%d\n", f1.numerator, f1.denominator,
    f2.numerator, f2.denominator, addedf.numerator, addedf.denominator);

struct fraction subtractedf = subtract_fractions(f1, f2);
printf("%d/%d - %d/%d = %d/%d\n", f1.numerator, f1.denominator,
    f2.numerator, f2.denominator, subtractedf.numerator,
    subtractedf.denominator);

struct fraction multipliedf = multiply_fractions(f1, f2);
printf("%d/%d * %d/%d = %d/%d\n", f1.numerator, f1.denominator,
    f2.numerator, f2.denominator, multipliedf.numerator,
    multipliedf.denominator);

struct fraction dividedf = divide_fractions(f1, f2);
printf("%d/%d / %d/%d = %d/%d\n", f1.numerator, f1.denominator,
    f2.numerator, f2.denominator, dividedf.numerator,
    dividedf.denominator);
return 0;

}
加法：struct fraction add_fractions(struct fraction f1, struct fraction f2)
{
f1.numerator *= f2.denominator;
f2.numerator *= f1.denominator;

struct fraction result = {
    f1.numerator + f2.numerator,
    f1.denominator * f2.denominator
};
result = reduce_fraction(result);

return result;

}`

减法：
`struct fraction subtract_fractions(struct fraction f1, struct fraction f2)
{
f1.numerator *= f2.denominator;
f2.numerator *= f1.denominator;

struct fraction result = {
    f1.numerator - f2.numerator,
    f1.denominator * f2.denominator
};
result = reduce_fraction(result);

return result;

}`

乘法：
`
struct fraction multiply_fractions(struct fraction f1, struct fraction f2)
{
struct fraction result = {
f1.numerator * f2.numerator,
f1.denominator * f2.denominator
};
result = reduce_fraction(result);

return result;

}`

除法：
`struct fraction divide_fractions(struct fraction f1, struct fraction f2)
{
struct fraction result = {
f1.numerator * f2.denominator,
f1.denominator * f2.numerator
};
result = reduce_fraction(result);

return result;

}`

源码：
`#include <stdio.h>

struct fraction {
int numerator;
int denominator;
};

// 求解最大公约数
int find_gcd(int n1, int n2);

// 将分数化为最简形式
struct fraction reduce_fraction(struct fraction f);

// 分数的四则运算
struct fraction add_fractions(struct fraction f1, struct fraction f2);
struct fraction subtract_fractions(struct fraction f1, struct fraction f2);
struct fraction multiply_fractions(struct fraction f1, struct fraction f2);
struct fraction divide_fractions(struct fraction f1, struct fraction f2);

int main(void)
{

struct fraction f = { 21, 3 };
struct fraction f1 = { 8, 64 };
struct fraction f2 = { 9, 711 };

struct fraction reducedf = reduce_fraction(f);
printf("%d/%d reduced to simplest terms: %d/%d\n", f.numerator,
    f.denominator, reducedf.numerator, reducedf.denominator);

struct fraction addedf = add_fractions(f1, f2);
printf("%d/%d + %d/%d = %d/%d\n", f1.numerator, f1.denominator,
    f2.numerator, f2.denominator, addedf.numerator, addedf.denominator);

struct fraction subtractedf = subtract_fractions(f1, f2);
printf("%d/%d - %d/%d = %d/%d\n", f1.numerator, f1.denominator,
    f2.numerator, f2.denominator, subtractedf.numerator,
    subtractedf.denominator);

struct fraction multipliedf = multiply_fractions(f1, f2);
printf("%d/%d * %d/%d = %d/%d\n", f1.numerator, f1.denominator,
    f2.numerator, f2.denominator, multipliedf.numerator,
    multipliedf.denominator);

struct fraction dividedf = divide_fractions(f1, f2);
printf("%d/%d / %d/%d = %d/%d\n", f1.numerator, f1.denominator,
    f2.numerator, f2.denominator, dividedf.numerator,
    dividedf.denominator);
return 0;

}

int find_gcd(int n1, int n2)
{
int temp;

while (n1 != 0) {
    temp = n2 % n1;
    n2 = n1;
    n1 = temp;
}

return n2;

}

struct fraction reduce_fraction(struct fraction f)
{
int gcd = find_gcd(f.numerator, f.denominator);
f.numerator /= gcd;
f.denominator /= gcd;
return f;
}

struct fraction add_fractions(struct fraction f1, struct fraction f2)
{
f1.numerator *= f2.denominator;
f2.numerator *= f1.denominator;

struct fraction result = {
    f1.numerator + f2.numerator,
    f1.denominator * f2.denominator
};
result = reduce_fraction(result);

return result;

}

struct fraction subtract_fractions(struct fraction f1, struct fraction f2)
{
f1.numerator *= f2.denominator;
f2.numerator *= f1.denominator;

struct fraction result = {
    f1.numerator - f2.numerator,
    f1.denominator * f2.denominator
};
result = reduce_fraction(result);

return result;

}

struct fraction multiply_fractions(struct fraction f1, struct fraction f2)
{
struct fraction result = {
f1.numerator * f2.numerator,
f1.denominator * f2.denominator
};
result = reduce_fraction(result);

return result;

}
struct fraction divide_fractions(struct fraction f1, struct fraction f2)
{
struct fraction result = {
f1.numerator * f2.denominator,
f1.denominator * f2.numerator
};
result = reduce_fraction(result);

return result;

}`

总结：
总的来说，这次作业的收获还是挺大的。之前没有接触过博客园，对于博客园的一些操作不是很熟悉，准确地说是很不熟悉，以至于这次作业在排版方面花了很长时间。最简单的，作业开头的那个表格，我自己搞了半天也没有达到想要的效果，最后还是在同学的帮助下完成的。以后会多加练习，争取熟练掌握博客园的一些操作技巧。最最重要的，我觉得还是编程能力，个人认为提高编程能力最好的办法还是多做，多想，多练习。

psp2.1	任务内容	计划完成需要的时间	实际完成需要的时间
planning	计划	15	10
estimate	估计这个任务需要多少时间，并规划大致工作步骤	12	15
development	开发	120	100
analysis	需求分析	10	8
design spec	生成设计文档	8	12
design review	设计复审	5	5
coding standard	代码规范	5	3
design	具体设计	10	16
coding	具体编码	35	37
code review	代码复审	6	8
test	测试	10	6
reporting	报告	6	8
test reporting	测试报告	3	2
size measurement	计算工作量	3	2
postmortem & process improvement plan	总结并提出改进计划	5	8