作业1：四则运算生成器

题目：完成一个基于控制台的四则运算程序，实现一个自动生成小学四则运算题目的命令行程序

从《构建之法》第一章的 “程序” 例子出发，像阿超那样，花二十分钟写一个能自动生成小学四则运算题目的命令行 “软件”。

一、程序设计及实现

  a.需求分析：

   1.四则运算是小学数学计算教学中的难点内容，也是学生必须熟练掌握的内容之一。因而设计两个数的四则运算题库，能了解并提高学生对四则运算的掌握程度

   2.小学四则运算以两个不超过100的整数，以及两个分数的四则运算为主。

    b.功能设计：   

    1.基本功能

• 除了整数以外，还要支持真分数的四则运算，真分数的运算，例如：1/6 + 1/8 = 7/24
• 运算符为 +, −, ×, ÷
• 并且要求能处理用户的输入，并判断对错，打分统计正确率
• 要求能处理用户输入的真分数， 如 1/2, 5/12 等

    2.部分代码说明：

    求公约数:  

int gcd(int x, int y)//求公约数

{

int temp;

while (x%y!=0)

{

temp = x%y;

x = y;

y = temp;

}

return y;

}

 生成随机数：

up = 1 + rand() % 10;

down = 1 + rand() % 10;

up1 = 1 + rand() % 10;

down1 = 1 + rand() % 10;

left = 1 + rand() % 100;

right = 1 + rand() % 100;

type = 1 + rand() % 8;

 

 整数加减乘除：

switch (type)

{

case 1:

cout << left;

cout << "+";

cout << right;

cout << "=?" << endl;

a[i] = left + right;

e[i] = 1;

break;//整数加法

case 2:

cout << left;

cout << "-";

cout << right;

cout << "=?" << endl;

a[i] = left - right;

e[i] = 2;

break;//整数减法

case 3:

cout << left;

cout << "*";

cout << right;

cout << "=?" << endl;

a[i] = left*right;

e[i] = 3;//整数乘法

break;

case 4:

cout << left;

cout << "÷";

cout << right;

cout << "=?" << endl;

result = left / right;

result = ((double)((int)((result + 0.005) * 100))) / 100;

a[i] = result;

e[i] = 4;

break;//整数除法

}

 分数的生成及加法（减乘除同理）

int gn;

if (up < down)

{

printf("%g/%g", up, down);

cout << "+";

if (up1 < down1)

{

printf("%g/%g=? ", up1, down1);

result1 = up*down1 + up1*down;

result2 = down1*down;

gn = gcd(result1, result2);

result1 = result1 / gn;

result2 = result2 / gn;

std::to_string(result1);

std::to_string(result2);

g[i] = result1 + '/' + result2;

 

 

}

else

{

printf("%g/%g=? ", down1, up1);

result1 = up*up1 + down1*down;

result2 = up1*down1;

gn = gcd(result1, result2);

result1 = result1 / gn;

result2 = result2 / gn;

std::to_string(result1);

std::to_string(result2);

g[i] = result1 + '/' + result2;

 

}

}

else

{

printf("%g/%g", down, up);

cout << "+";

if (up1 < down1)

{

printf("%g/%g=? ", up1, down1);

result1 = down1*down + up1*up;

result2 = up*down1;

gn = gcd(result1, result2);

result1 = result1 / gn;

result2 = result2 / gn;

std::to_string(result1);

std::to_string(result2);

g[i] = result1 + '/' + result2;

}

 

 

else

{

printf("%g/%g=? ", down1, up1);

result1 = down*up1 + down1*up;

result2 = up*up1;

gn = gcd(result1, result2);

result1 = result1 / gn;

result2 = result2 / gn;

std::to_string(result1);

std::to_string(result2);

g[i] = result1 + '/' + result2;

}

 

}

 

e[i] = 5;

break;

 

输入答案并判断对错正确率：

cout << "请输入答案" << endl;

for (i = 0; i < n; i++)

{

if (e[i] < 5)

{

cin >> b[i];

if (b[i] == a[i])

count += 1;

 

}

if (e[i] >= 5)

{

cin >> f[i];

if (f[i].compare(g[i]) == 0)

count += 1;

else

continue;

 

}

 

}//判断对错

double rate = count/ n;

cout << "正确率：";

cout << rate;

c.运行结果截图：

2.展示psp:

PSP2.1	Personal Software Process Stages	Time (m) Senior Student	Time (m)
Planning	计划	2h	1.5h
· Estimate	估计这个任务需要多少时间	8h	10h
Development	开发	--	--
· Analysis	需求分析 (包括学习新技术)	10min	10min
· Design Spec	生成设计文档	20min	15min
· Design Review	设计复审	--	--
· Coding Standard	代码规范	5min	8min
· Design	具体设计	40min	50min
· Coding	具体编码	6h	7h
· Code Review	代码复审	1h	1.5h
· Test	测试（自我测试，修改代码，提交修改）	3h	3h
Reporting	报告	30min	25min
·	测试报告	--	--
·	计算工作量	5min	5min
·	并提出过程改进计划	--	--

开发软件：vs2013

  三、小结：

     第一次做软件工程的作业 ，编程水平有限导致编写代码花费时间长，很多地方不完善。

码云地址：https://coding.net/u/linzhao/p/sizeyunsuan/git/tree/master/