C++程序设计(第二版)谭浩强----程序题课后习题答案第三章

2.

#define _USE_MATH_DEFINES
#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
int main()
{
    float r, h, l, S, S1, V, V1;
    cin >> r >> h;
    l = 2 * M_PI * r;
    S = M_PI * r * r;
    S1 = 4 * M_PI * r * r;
    V = 4 / 3 * M_PI * r * r * r;
    V1 = S * h;
    cout << setiosflags(ios::fixed) << setprecision(2);
    cout << "圆周长 l = " << l << '	' << "圆面积 S = " << S << endl;
    cout << "圆球表面积 S1 = " << S1 << '	' << "圆球体积 V = " << V << endl;
    cout << "圆柱体积 V1 = " << V1 << endl;
    return 0;
}

结果：

3.

#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
    float F, c;
    cout << "华氏温度 F = ";
    cin >> F;
    cout << setiosflags(ios::fixed) << setprecision(2);
    c = (5.0 / 9.0) * (F - 32);
    cout << "摄氏温度c = " << c << endl;
    return 0;
}

结果：

 4.

c1,c2定义为字符型

#include <iostream>
using namespace std;
int main()
{
    char c1, c2;
    cout << "请输入两个字符";
    c1 = getchar();
    c2 = getchar();
    cout << "putchar 输出结果";
    putchar(c1);
    putchar('	');
    putchar(c2);
    putchar('
');
    cout << "cout输出结果";
    cout << c1 << '	' << c2 << endl;
    return 0;
}

结果：

c1,c2定义为整形

#include <iostream>
using namespace std;
int main()
{
    int c1, c2;
    cout << "请输入两个字符";
    c1 = getchar();
    c2 = getchar();
    cout << "putchar 输出结果";
    putchar(c1);
    putchar('	');
    putchar(c2);
    putchar('
');
    cout << "cout输出结果";
    cout << c1 << '	' << c2 << endl;
    return 0;
}

结果：

定义为整形即可输出ASCII码。

8.

0

1

1

0

1

9.

#include <iostream>
using namespace std;
int main()
{
    int compare(int x, int y, int z);
    int a, b, c, temp, max;
    cout << "输入三个整数a b c" << endl;
    cin >> a >> b >> c;
    //第一种方法
    /*if ((a > b) && (a > c))
    cout << "最大的数为a = " << a << endl;
    else if((b>a)&&(b>c))
    cout << "最大的数为b = " << b << endl;
    else
    cout << "最大的数为c = " << c << endl;*/
    //第二种方法
    /*if(a<b)
    if(b<c)
    cout << "最大的数为c = " << c << endl;
    else
    cout << "最大的数为b = " << b << endl;
    else
    if(a<c)
    cout << "最大的数为c = " << c << endl;
    else
    cout << "最大的数为a = " << a << endl;*/
    //第三种方法
    /*temp = (a > b) ? a : b;
    max = (temp > c) ? temp : c;
    cout << "最大的数为 " << max << endl;*/
    max = compare(a, b, c);
    cout << "最大的数为 " << max << endl;
    return 0;
}
int compare(int x, int y, int z)
{
    int temp, max;
    temp = (x > y) ? x : y;
    max = (temp > z) ? temp : z;
    return max;
}

结果：

10.

#include <iostream>
using namespace std;
int main()
{
    int x, y;
    cout << "输入 x = ";
    cin >> x;
    if (x < 1)
        y = x;
    else
        if (x >= 1 && x < 10)
            y = 2 * x - 1;
        else
            y = 3 * x - 11;
    cout << "输出 y = " << y << endl;
    return 0;

结果：

11.

#include <iostream>
using namespace std;
int main()
{
    int grade;
    while (1)
    {
        cout << "输入学生成绩grade = ";
        cin >> grade;
        if (grade < 0 || grade > 100)
            cout << "成绩输入错误,请重新输入！" << endl;
        else
            switch ((int)grade / 10)
            {
            case 10: cout << grade << "分成绩等级为A" << endl; break;
            case 9: cout << grade << "分成绩等级为A" << endl; break;
            case 8: cout << grade << "分成绩等级为B" << endl; break;
            case 7: cout << grade << "分成绩等级为C" << endl; break;
            case 6: cout << grade << "分成绩等级为D" << endl; break;
            default: cout << grade << "分成绩等级为E" << endl; break;
            }
    }
    return 0;
}

结果：

12.

#include <iostream>
using namespace std;
int main()
{
    long int a;
    cout << "输入正整数 a = ";
    while (1)
    {
        cin >> a;
        if (a > 99999)
        {
            cout << "输入错误,请重新输入！" << endl;
            continue;
        }
        else if (a / 10000 > 0)
            cout << "a 为5位数 " << a / 10000 + (a % 10000) / 1000 * 10 + (a % 1000) / 100 * 100 + (a % 100) / 10 * 1000 + (a % 10) * 10000 << endl;
        else if (a / 1000 > 0)
            cout << "a 为4位数 " << a / 1000 + (a % 1000) / 100 * 10 + (a % 100) / 10 * 100 + (a % 10) * 1000 << endl;
        else if (a / 100 > 0)
            cout << "a 为3位数 " << a / 100 + (a % 100) / 10 * 10 + (a % 10) * 100 << endl;
        else if (a / 10 > 0)
            cout << "a 为2位数 " << a / 10 + (a % 10) * 10 << endl;
        else
            cout << "a 为1位数 " << a << endl;

    }
    return 0;
}

结果：

13.

#include<iostream>
using namespace std;
int main()
{
    float i;
    int c;
    while (1)
    {
        /*cout << "输入当月利润为 i = ";
        cin >> i;
        if (i <= 10)
        cout << "应发奖金为 " << i*0.1 << "万元" << endl;
        else if (i <= 20 && i >= 10)
        cout << "应发奖金为 " << 10 * 0.1 + (i - 10)*0.075 << "万元" << endl;
        else if (i <= 40 && i >= 20)
        cout << "应发奖金为 " << 10 * 0.1 + 10 * 0.075 + (i - 20)*0.05 << "万元" << endl;
        else if (i <= 60 && i >= 40)
        cout << "应发奖金为 " << 10 * 0.1 + 10 * 0.075 + 20 * 0.05 + (i - 40)*0.03 << "万元" << endl;
        else if (i <= 100 && i >= 60)
        cout << "应发奖金为 " << 10 * 0.1 + 10 * 0.075 + 20 * 0.05 + 20 * 0.03 + (i - 60)*0.015 << "万元" << endl;
        else
        cout << "应发奖金为 " << 10 * 0.1 + 10 * 0.075 + 20 * 0.05 + 20 * 0.03 + 40 * 0.015 + (i - 100)*0.01 << "万元" << endl;*/
        cout << "输入当月利润为 i = ";
        cin >> i;
        c = i / 10;
        if (c > 10) c = 10;
        switch (c)
        {
        case 0: cout << "应发奖金为 " << i*0.1 << "万元" << endl; break;
        case 1: cout << "应发奖金为 " << 10 * 0.1 + (i - 10)*0.075 << "万元" << endl; break;
        case 2:
        case 3: cout << "应发奖金为 " << 10 * 0.1 + 10 * 0.075 + (i - 20)*0.05 << "万元" << endl; break;
        case 4:
        case 5: cout << "应发奖金为 " << 10 * 0.1 + 10 * 0.075 + 20 * 0.05 + (i - 40)*0.03 << "万元" << endl; break;
        case 6:
        case 7:
        case 8:
        case 9: cout << "应发奖金为 " << 10 * 0.1 + 10 * 0.075 + 20 * 0.05 + 20 * 0.03 + (i - 60)*0.015 << "万元" << endl; break;
        case 10: cout << "应发奖金为 " << 10 * 0.1 + 10 * 0.075 + 20 * 0.05 + 20 * 0.03 + 40 * 0.015 + (i - 100)*0.01 << "万元" << endl; break;
        }

    }
    return 0;

结果：

14.

#include<iostream>
using namespace std;
int main()
{
    void sort(int m, int j, int k, int l);
    int a, b, c, d;
    cout << "请输入四个整数 ";
    cin >> a >> b >> c >> d;
    sort(a, b, c, d);
    return 0;
}
void sort(int m, int j, int k, int l)
{
    int temp;
    if (m > j) { temp = m; m = j; j = temp; }
    if (m > k) { temp = m; m = k; k = temp; }
    if (m > l) { temp = m; m = l; l = temp; }
    if (j > k) { temp = j; j = k; k = temp; }
    if (j > l) { temp = j; j = l; l = temp; }
    if (k > l) { temp = k; k = l; l = temp; }
    cout << "从小到大顺序输出为：" << m << '	' << j << '	' << k << '	' << l << '	' << endl;
}

结果：

15.

#include<iostream>
using namespace std;
int main()
{
    int m, n, temp, p;
    while (1)
    {
        temp = 1;
        cout << "请输入两个正整数：";
        cin >> m >> n;
        p = m * n;
        while (temp != 0)
        {
            if (m > n)
            {
                temp = m % n;
                m = n; n = temp;
                if (temp == 0)
                {
                    cout << "m 和 n 的最大公约数为：" << m << endl;
                    cout << "m 和 n 的最小公倍数为：" << p / m << endl;
                }
            }
            else
            {
                temp = n % m;
                n = m; m = temp;
                if (temp == 0)
                {
                    cout << "m 和 n 的最大公约数为：" << n << endl;
                    cout << "m 和 n 的最小公倍数为：" << p / n << endl;
                }
            }
        }
    }
    return 0;
}

结果：

16.

#include <iostream>
using namespace std;
int main()

{
    char c;
    int l = 0, s = 0, d = 0, o = 0;
    cout << "请输入一行字符" << endl;
    while (1)
    {
        while ((c = getchar()) != '
')
        {
            if (c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z')
                l++;
            else if (c == ' ')
                s++;
            else if (c >= '0' && c <= '9')
                d++;
            else
                o++;
        }

        cout << "这一行字符中" << "英文字母" << l << "个" << endl;
        cout << "这一行字符中" << "空格" << s << "个" << endl;
        cout << "这一行字符中" << "数字" << d << "个" << endl;
        cout << "这一行字符中" << "其他字符" << o << "个" << endl;
        l = 0, s = 0, d = 0, o = 0;
    }return 0;

}

结果：

17.

#include<iostream>
using namespace std;
int main()
{
    int a, Sn = 0, n, i = 1, temp = 0;
    cout << "输入 a 的值: ";
    cin >> a;
    cout << "输入 n 的值: ";
    cin >> n;
    while (i <= n)
    {
        temp = temp + a;
        Sn = Sn + temp;
        a = a * 10;
        i++;
    }
    cout << "Sn = " << Sn << endl;
    return 0;
}

结果：

18.

#include<iostream>
using namespace std;
int main()
{
    int n = 1, S = 0, temp = 1;
    while (n <= 20)
    {
        temp = temp*n;
        S = S + temp;
        n++;
    }
    cout << S << endl;
    return 0;
}

结果：

19.

#include<iostream>
using namespace std;
int main()
{
    int a, b, i, j, k;
    for (a = 100; a < 1000; a++)
    {
        i = a / 100;
        j = (a % 100) / 10;
        k = a % 10;
        b = i*i*i + j*j*j + k*k*k;
        if (a == b)
            cout << a << " 是水仙花数" << endl;
    }
    return 0;
}

结果：

20.

#include <iostream>
using namespace std;
int main()
{
    int m, n, i;
    for (m = 2; m<1000; m++)
    {
        n = 0;
        for (i = 1; i<m; i++)
            if ((m%i) == 0) n = n + i;
        if (n == m)
        {
            cout << m << ",its factors are:" ;
            for (i = 1; i<m; i++)
                if (m%i == 0) cout << i << " ";
            cout << endl;
        }

    }
    return 0;
}

结果：

21.

#include <iostream>
using namespace std;
int main()
{
    int i, t, n = 20;
    double a = 2, b = 1, s = 0;
    for (i = 1; i <= n; i++)
    {
        s = s + a / b;
        t = a;
        a = a + b; // 将前一项分子与分母之和作为下一项的分子
        b = t; // 将前一项的分子作为下一项的分母
    }
    cout << "sum=" << s << endl;
    return 0;
}

结果：

22.

#include <iostream>
using namespace std;
int main()
{
    int n = 1, i;
    for (i = 1; i < 10; i++)
    {
        n = (n + 1) * 2;
    }
    cout << "桃子总数" << n << endl;
    return 0;
}

结果：

23.

#include <iostream>
#include <cmath>
using namespace std;
int main()
{
    float a, x0, x1;
    cout << "enter a positive number: ";
    cin >> a; 
    x0 = sqrt(double(a));
    x1 = (x0 + a / x0) / 2;
    do
    {
        x0 = x1;
        x1 = (x0 + a / x0) / 2;
    }
    while (fabs(x0 - x1) >= 1e-5);
    cout << "The square root of " << a << " is " << x1 << endl;
    return 0;
}

结果：

24.

#include <iostream>
using namespace std;
int main()
{
    int i, k;
    for (i = 0; i <= 3; i++) // 输出上面4行*号
    {
        for (k = 0; k <= 2 * i; k++)
            cout << "*"; // 输出*号
        cout << endl; //输出完一行*号后换行
    }
    for (i = 0; i <= 2; i++) // 输出下面3行*号
    {
        for (k = 0; k <= 4 - 2 * i; k++)
            cout << "*"; // 输出*号
        cout << endl; // 输出完一行*号后换行
    }
    return 0;
}

结果：

25.

#include <iostream>
using namespace std;
int main()
{
    char i, j, k; /* i是a的对手;j是b的对手;k是c的对手*/
    for (i = 'X'; i <= 'Z'; i++)
        for (j = 'X'; j <= 'Z'; j++)
            if (i != j)
                for (k = 'X'; k <= 'Z'; k++)
                    if (i != k && j != k)
                        if (i != 'X' && k != 'X' && k != 'Z')
                            cout << "A--" << i << " B--" << j << " C--" << k << endl;

    return 0;
}

结果：

参考链接：http://blog.csdn.net/zhengxiaoyang995926/article/details/79491582