实验一

1.(1)用if...else实现简单的菜单程序

#include<iostream>
using namespace std;
int main()
{
    char c;
    cout << "Menu: A(dd) D(elete) S(ort) Q(uit):";
    cin >> c;
    while (c) {
        if (c == 'A')
            cout << "number has been added" << endl;
        else if (c == 'D')
            cout << "number has been deleted" << endl;
        else if (c == 'S')
            cout << "number has been sorted" << endl;
        else if (c == 'Q')
            break;
        else  cout << "input error!" << endl;
        cout << "Menu: A(dd) D(elete) S(ort) Q(uit):";
        cin >> c;
    }
    return 0;
}

 

1.(2)用switch实现简单的菜单程序

#include<iostream>
using namespace std;
int main()
{
    char c;
    cout << "Menu: A(dd) D(elete) S(ort) Q(uit):";
    cin >> c;
    while (c!='Q') 
    {
        switch (c)
        {
        case 'A':cout << "number has been added" << endl; break;
        case 'D':cout << "number has been deleted" << endl; break;
        case 'S':cout << "number has been sorted" << endl; break;
        default:cout << "input error!" << endl;
        }
        cout << "Menu: A(dd) D(elete) S(ort) Q(uit):";
        cin >> c;
    }
    return 0;
}

2.(1)用while输出1-100的素数

#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
    int j = 0, n = 2, i;
    while (n < 100)
    {
        i = 2;
        while (i <= n - 1) {
            if (n%i++ == 0)
            {
                break;
            }
        }
        if (i > n - 1)
        {
            cout << setw(5) << n; j++;
            if (j % 5 == 0)
                cout << endl;
        }

        n++;
    }
    return 0;
}

2.(2)用for输出1-100的素数

#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
    int j = 0, n, i,f=1;
    for (n = 2; n < 100; n++)
    {
        for(i=2;i<=n-1;i++)
        {
            if (n%i == 0) 
            {
                f = 0; break;
            }
        }
        if(i>n-1)
        {
            cout << setw(5) << n; j++;
            if(j%5==0)
            cout << endl;
        }
        
    }
    return 0;
}

2.(3)用do...while输出1-100的素数

#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
    int j = 0, n = 2, i;
    do
    {
        i = 2;
        do
        {
            if (n%i++ == 0)
            {
                break;
            }
        } while (i <= n - 1);
            if (i > n - 1)
            {
                cout << setw(5) << n; j++;
                if (j % 5 == 0)
                {
                    cout << endl;
                }
            }
        
        n++;
    } while (n < 100);
    return 0;
}

3.(1)用while生成一个随机数并猜测

#include<iostream>
using namespace std;
#include<cstdlib>
#include<ctime>
int main()
{
    int n, x;
    srand((unsigned)time(0));
    n = (100*(int)rand() / 100 + 1)%100;
    cin >> x;
    while(x!=n)
    {
        if (x < n) cout << "The number is bigger" << endl;
        else if (x > n) cout << "The number is lower" << endl;
        cin >> x;
    }
    cout << "You are right" << endl;
}

3.(2)用do...while生成一个随机数并猜测

#include<iostream>
using namespace std;
#include<cstdlib>
#include<ctime>
int main()
{
    int n, x;
    srand((unsigned)time(0));
    n = (100 * (int)rand() / 100 + 1) % 100;
    cin >> x;
    do
    {
        if (x < n) cout << "The number is bigger" << endl;
        else if (x > n) cout << "The number is lower" << endl;
        cin >> x;
    } while (x != n);
    cout << "You are right" << endl;
}

4.五种球，任取三个，有多少种取法

#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
    int  i, j, k;
    for (i = 0; i <= 4; i++)
    {
        for (j = i + 1; j <= 4; j++)
        {
            if (j == i) continue;
            for (k = j + 1; k <= 4; k++)
            {
                if (k == i || k == j) continue;
                cout << setw(5) << i << setw(5) << j << setw(5) << k << endl;
            }
        }
    }
}

实验总结与体会

1.这次实验让我练习了一下c++的格式

2.知道了随机函数的用法，虽然可能是错的

3.复习了一下上学期学的C语言知识