//文中有格式错误请无视
//这个编辑器一言难尽
实验目的
1. 掌握c++中类c部分的编程知识: 数据类型，常量，变量，运算符，表达式，分支结构，循环结构
2. 掌握C++中数据输入和输出的基本方法
3. 熟练使用c++程序开发环境，掌握c++程序编写、编译、运行、调试的方法
实验准备
1. 简单的c++程序结构 学习/复习教材「2.1.3 C++程序实例」
2. c++中数据输入输出的基本方法 学习/复习教材2.3节，学习C++中I/O流、预定义的插入符<<和提取符>>的基本用法。
3. if语句、switch语句、while语句、do…while语句的用法 学习/复习教材2.4节，通过示例理解背后简单算法及c++分支语句、循环语句的用法
4. 自定义数据类型: typedef，枚举类型用法 学习/复习教材2.5节，结合示例理解枚举类型和int型在类型转换时的注意事项
实验内容
Part2: 编程练习
教材第2章习题2-28 简单的菜单程序
教材第2章习题2-29 穷举法求质数
教材第2章习题2-32 猜数
教材第2章习题2-34排列组合
实验结论
2-28简单的菜单程序（if-else
Code：
1 #include<iostream>
2 using namespace std;
3 int main()
4 {
5 cout<<"Menu:A(dd) D(elete) S(ort) Q(uit)";
6 cout<<"Select one:";
7 char k;
8 while(cin>>k)
9 {
10 if(k=='A')
11 cout<<"Data has added.\n"<<"Menu:A(dd) D(elete) S(ort) Q(uit)"<<"Select one:";
12 else if(k=='D')
13 cout<<"Data has deleted.\n"<<"Menu:A(dd) D(elete) S(ort) Q(uit)"<<"Select one:";
14 else if(k=='S')
15 cout<<"Data has sorted.\n"<<"Menu:A(dd) D(elete) S(ort) Q(uit)"<<"Select one:";
16 else if(k=='Q')
17 break;
18 else
19 cout<<"No such choice,please select again.\n"<<"Menu:A(dd) D(elete) S(ort) Q(uit)"<<"Select one:";
20 }
21 return 0;
22 }
Screenshot:
(switch
Code:
1 #include<iostream>
2 using namespace std;
3 int main()
4 {
5 cout<<"Menu:A(dd) D(elete) S(ort) Q(uit)";
6 cout<<"Select one:";
7 char k;
8 while(cin>>k&&k!='Q')
9 {
10 switch(k)
11 {
12 case 'A':
13 cout<<"Data has added.\n"<<"Menu:A(dd) D(elete) S(ort) Q(uit)"<<"Select one:";
14 continue;
15 case 'D':
16 cout<<"Data has deleted.\n"<<"Menu:A(dd) D(elete) S(ort) Q(uit)"<<"Select one:";
17 continue;
18 case 'S':
19 cout<<"Data has sorted.\n"<<"Menu:A(dd) D(elete) S(ort) Q(uit)"<<"Select one:";
20 continue;
21 default:cout<<"No such choice,please select again.\n"<<"Menu:A(dd) D(elete) S(ort) Q(uit)"<<"Select one:";
22 }
23 }
24 return 0;
25 }
Screenshop:
2-29 穷举法求质数（while
Code:
1 #include<iostream>
2 #include<cmath>
3 #include<iomanip>
4 using namespace std;
5 int main()
6 {
7 cout<<"1~100间的质数为："<<endl;
8 int x=1;
9 int a,b,c=0;
10 while(x<=100)
11 {
12 a=sqrt(x);
13 if(x!=1)
14 {
15 b=2;
16 while(x%b!=0&&b<=a)
17 b++;
18 if(b>a)
19 {
20 c++;
21 cout<<setw(5)<<x;
22 if(c%5==0)
23 cout<<"\n";
24 }
25 }
26 x++;
27 }
28 return 0;
29 }
Screenshop:
(for
Code:
1 #include<iostream>
2 #include<cmath>
3 #include<iomanip>
4 using namespace std;
5 int main()
6 {
7 cout<<"1~100间的质数为："<<endl;
8 int x;
9 int a,b,c=0;
10 for(x=1;x<=100;x++)
11 {
12 a=sqrt(x);
13 if(x==1)
14 continue;
15 else
16 {
17 for(b=2;b<=a;b++)
18 if(x%b==0)
19 break;
20 if(b>a)
21 {
22 c++;
23 cout<<setw(5)<<x;
24 if(c%5==0)
25 cout<<"\n";
26 }
27 }
28 }
29 return 0;
30 }
Screenshop:
(do-while
Code:
1 #include<iostream>
2 #include<cmath>
3 #include<iomanip>
4 using namespace std;
5 int main()
6 {
7 cout<<"1~100间的质数为："<<endl;
8 int x=0;
9 int a,b,c=0;
10 do
11 {
12 x++;
13 a=sqrt(x);
14 if(x!=1)
15 {
16 b=1;
17 do
18 {
19 b++;
20 }while(x%b!=0&&b<=a);
21 if(b>a)
22 {
23 c++;
24 cout<<setw(5)<<x;
25 if(c%5==0)
26 cout<<"\n";
27 }
28 }
29 }while(x<100);
30 return 0;
31 }
Screenshop:
2-32 猜数(while
Code:
1 #include<iostream>
2 #include<ctime>
3 #include<cstdlib>
4 using namespace std;
5 int main()
6 {
7 int x;
8 int a;
9 srand(time(NULL));
10 x=1+rand()%(100-1+1);
11 cout<<"Your guess number is(1~100): ";
12 cin>>a;
13 while(a!=x)
14 {
15 if(a<x)
16 {
17 cout<<"Bigger than the number."<<endl;
18 cout<<"Your guess number is(1~100): ";
19 cin>>a;
20 }
21 else
22 {
23 cout<<"Lower than the number. "<<endl;
24 cout<<"Your guess number is(1~100): ";
25 cin>>a;
26 }
27 }
28 cout<<"Congretulations.You guessed it.~";
29 return 0;
30 }
Screenshop:
(do-while
Code:
1 #include<iostream>
2 #include<ctime>
3 #include<cstdlib>
4 using namespace std;
5 int main()
6 {
7 int x;
8 int a;
9 srand(time(NULL));
10 x=1+rand()%(100-1+1);
11 cout<<"Your guess number is(1~100): ";
12 do
13 {
14 cin>>a;
15 if(a<x)
16 {
17 cout<<"Bigger than the number."<<endl;
18 cout<<"Your guess number is(1~100): ";
19 }
20 else if(a>x)
21 {
22 cout<<"Lower than the number. "<<endl;
23 cout<<"Your guess number is(1~100): ";
24 }
25 }while(a!=x);
26 cout<<"Congretulations.You guessed it.~";
27 return 0;
28 }
Screenshop:
//暴力循环
2-34排列组合(排列
Code:
1 #include<iostream>
2 #include<iomanip>
3 using namespace std;
4 int main()
5 {
6 int x[3],k=0,i;
7 for(x[0]=1;x[0]<=5;x[0]++)
8 {
9 for(x[1]=1;x[1]<=5;x[1]++)
10 {
11 if(x[1]==x[0])
12 continue;
13 else
14 {
15 for(x[2]=1;x[2]<=5;x[2]++)
16 {
17 if(x[2]==x[0]||x[2]==x[1])
18 continue;
19 else
20 {
21 k++;
22 for(i=0;i<=2;i++)
23 {
24 if(i!=2)
25 {
26 switch(x[i])
27 {
28 case 1:
29 cout<<"red ";
30 continue;
31 case 2:
32 cout<<"yellow ";
33 continue;
34 case 3:
35 cout<<"blue ";
36 continue;
37 case 4:
38 cout<<"white ";
39 continue;
40 case 5:
41 cout<<"black ";
42 }
43 }
44 else
45 {
46 switch(x[i])
47 {
48 case 1:
49 cout<<"red\n";
50 continue;
51 case 2:
52 cout<<"yellow\n";
53 continue;
54 case 3:
55 cout<<"blue\n";
56 continue;
57 case 4:
58 cout<<"white\n";
59 continue;
60 case 5:
61 cout<<"black\n";
62 }
63 }
64 }
65 }
66 }
67 }
68 }
69 }
70 cout<<"Total: "<<k;
71 return 0;
72 }
Screenshop:
（组合
Code:
1 #include<iostream>
2 #include<iomanip>
3 using namespace std;
4 int main()
5 {
6 int x[3],k=0,i;
7 for(x[0]=1;x[0]<=5;x[0]++)
8 for(x[1]=x[0]+1;x[1]<=5;x[1]++)
9 for(x[2]=x[1]+1;x[2]<=5;x[2]++)
10 {
11 k++;
12 for(i=0;i<=2;i++)
13 {
14 if(i!=2)
15 {
16 switch(x[i])
17 {
18 case 1:
19 cout<<"red ";
20 continue;
21 case 2:
22 cout<<"yellow ";
23 continue;
24 case 3:
25 cout<<"blue ";
26 continue;
27 case 4:
28 cout<<"white ";
29 continue;
30 case 5:
31 cout<<"black ";
32 }
33 }
34 else
35 {
36 switch(x[i])
37 {
38 case 1:
39 cout<<"red\n";
40 continue;
41 case 2:
42 cout<<"yellow\n";
43 continue;
44 case 3:
45 cout<<"blue\n";
46 continue;
47 case 4:
48 cout<<"white\n";
49 continue;
50 case 5:
51 cout<<"black\n";
52 }
53 }
54 }
55 }
56 cout<<"Total: "<<k;
57 return 0;
58 }
Screenshop:
实验总结
这次试验主要是类C的部分，CPP的特性我还没有完全体会到（从I/O流已经可以看出些特点的程度）。
在进行多次判断时还是用switch更方便。
多数时候for循环较为好用。
写程序时尽量避免嵌套过多层循环，严重拖慢编译和运行速度。
srand(time(NULL));
x=1+rand()%(100-1+1);
以此来取一定范围内的随机数。
枚举数据类型不同于整型或字符型。