《C程序设计（第五版）》谭浩强编著—习题—第四章

4.

#include 
#include 

int main()
{
    int a,b,c,temp;
    scanf("%d %d %d",&a,&b,&c);
    if(a < b){
        //交换a,b的值，用a保存最大值
        temp = a;
        a = b;
        b = temp;

    }
    if(a < c){
        temp = a;
        a = c;
        c = temp;
    }
    printf("最大值为: %d",a);
    return 0;
}

5.

#include 
#include 
#include

int main()
{
    int num,sqrtNum;
    scanf("%d",&num);
    if(num >= 1000){
        printf("请重新输入小于1000的数\n");
        scanf("%d",&num);
    }
    sqrtNum = sqrt(num);
    printf("%d平方根整数部分为:%d",num,sqrtNum);
    return 0;
}

6.

#include 
#include 

int main()
{
    int x, y;
    printf("请输入x的值:\n");
    scanf("%d", &x);
    if(x < 1){
        y = x;
    }
    else if(x < 10){
        y = 2 * x - 1;
    }
    else{
        y = 3 * x - 11;
    }
    printf("y的值为: %d", y);
    return 0;
}

7.

#include 
#include 

int main()
{
    float grade;
    printf("请输入成绩\n");
    scanf("%f",&grade);
    switch((int)grade/10)
    {
    case 0:
    case 1:
    case 2:
    case 3:
    case 4:
    case 5: printf("成绩等级为E\n");break;
    case 6: printf("成绩等级为D\n");break;
    case 7: printf("成绩等级为C\n");break;
    case 8: printf("成绩等级为B\n");break;
    case 9:
    case 10:printf("成绩等级为A\n");break;
    }
    return 0;
}

9.

#include 
#include 

int main()
{
    int num,digit,firstDigit,secondDigit,thirdDigit,fourthDigit,fifthDigit;
    printf("请输入不多于五位的正整数\n");
    scanf("%d",&num);
    if(num < 1||num >99999){
        printf("输入出错!");
    }
    else
    {
        //判断位数
        if(num > 9999){
            digit = 5;
        }
        else if(num >999){
            digit = 4;
        }
        else if(num > 99){
            digit = 3;
        }
        else if(num > 9){
            digit = 2;
        }
        else digit = 1;
        printf("该数字是%d位数",digit);
        //分别输出每一位数字
        firstDigit = num/10000;
        secondDigit = (num%10000)/1000;
        thirdDigit = (num%1000)/100;
        fourthDigit = (num%100)/10;
        fifthDigit = num%10;
        switch(digit)
        {
            case 5:printf("每一位数字为：%d,%d,%d,%d,%d\n",firstDigit,secondDigit,thirdDigit,fourthDigit,fifthDigit);
                   printf("倒序输出结果为: %d%d%d%d%d",fifthDigit,fourthDigit,thirdDigit,secondDigit,firstDigit);
                   break;
            case 4:printf("每一位数字为：%d,%d,%d,%d\n",secondDigit,thirdDigit,fourthDigit,fifthDigit);
                   printf("倒序输出结果为: %d%d%d%d",fifthDigit,fourthDigit,thirdDigit,secondDigit);
                   break;
            case 3:printf("每一位数字为：%d,%d,%d\n",thirdDigit,fourthDigit,fifthDigit);
                   printf("倒序输出结果为: %d%d%d",fifthDigit,fourthDigit,thirdDigit);
                   break;
            case 2:printf("每一位数字为：%d,%d\n",fourthDigit,fifthDigit);
                   printf("倒序输出结果为: %d%d",fifthDigit,fourthDigit);
                   break;
            case 1:printf("每一位数字为：%d\n",fifthDigit);
                   printf("倒序输出结果为: %d",fifthDigit);
                   break;
        }


    }
    return 0;
}

10.

（1）

#include 
#include 

int main()
{
    int i;
    double addition;
    printf("请输入当月利润!\n");
    scanf("%d", &i);
    if(i <= 100000){
        addition = i * 0.1;
    }
    else if(i <= 200000){
        addition = 100000 * 0.1 + (i-100000)*0.075;
    }
    else if(i <= 400000){
        addition = 100000*0.1 + 100000 * 0.075 + (i-200000)*0.05;
    }
    else if(i <= 600000){
        addition = 100000 * 0.1 + 100000 * 0.075 + 200000*0.05 + (i-400000)*0.03;
    }
    else if(i <= 1000000){
        addition = 100000 * 0.1 + 100000 * 0.075 + 200000*0.05 + 200000*0.03 + (i-600000)* 0.015;
    }
    else if(i > 1000000){
        addition = 100000 * 0.1 + 100000 * 0.075 + 200000*0.05 + 200000*0.03 + 400000*0.015 + (i-1000000)*0.01;
    }
    printf("奖金为:%.2f\n", addition);
    return 0;
}

（2）

#include 
#include 

int main()
{
    int i,total;
    double addition;
    printf("请输入当月利润!\n");
    scanf("%d", &i);
    if(i > 1000000)
        total = 10;
    else
        total = i/100000;
    switch(total)
    {
    case 0:
        addition = i * 0.1;
        break;
    case 1:
        addition = 100000 * 0.1 + (i-100000)*0.075;
        break;
    case 2:
    case 3:
        addition = 100000*0.1 + 100000 * 0.075 + (i-200000)*0.05;
        break;
    case 4:
    case 5:
        addition = 100000 * 0.1 + 100000 * 0.075 + 200000*0.05 + (i-400000)*0.03;
        break;
    case 6:
    case 7:
    case 8:
    case 9:
        addition = 100000 * 0.1 + 100000 * 0.075 + 200000*0.05 + 200000*0.03 + (i-600000)* 0.015;
        break;
    case 10:
        addition = 100000 * 0.1 + 100000 * 0.075 + 200000*0.05 + 200000*0.03 + 400000*0.015 + (i-1000000)*0.01;
        break;
    }
    printf("奖金为:%.2f\n", addition);
    return 0;
}

11.

#include 
#include 

int main()
{
    int a, b, c, d,temp;
    printf("请输入四个整数:\n");
    scanf("%d %d %d %d",&a,&b,&c,&d);
    //选出abcd四个数最小的保存在a
    if(a > b){
        temp = a;
        a = b;
        b = temp;
    }
    if(a > c){
        temp = a;
        a = c;
        c = temp;

    }
    if(a > d){
        temp = a;
        a = d;
        d = temp;
    }
    //选出bcd最小的存在b
    if(b > c){
        temp = b;
        b= c;
        c = temp;
    }
    if(b > d){
        temp = b;
        b= d;
        d = temp;
    }
    //选出cd最小的保存在c
    if(c > d){
        temp = c;
        c = d;
        d = temp;
    }
    printf("按从小到大排序结果为:\n%d,%d,%d,%d,",a,b,c,d);
    return 0;
}

12.

#include 
#include 

int main()
{
    double x1 = 2, y1 = 2, x2 = -2, y2 = 2, x3 = -2, y3 = -2, x4 = 2, y4 = -2,x,y;
    printf("请输入x和y的坐标:\n");
    scanf("%lf %lf",&x,&y);
    if(((x-x1)*(x-x1) + (y-y1)*(y-y1)) < 1){
        printf("该点的高度为10m");
    }
    else if(((x-x2)*(x-x2) + (y-y2)*(y-y2)) < 1){
        printf("该点的高度为10m");
    }
    else if(((x-x3)*(x-x3) + (y-y3)*(y-y3)) < 1){
        printf("该点的高度为10m");
    }
    else if(((x-x4)*(x-x4) + (y-y4)*(y-y4)) < 1){
        printf("该点的高度为10m");
    }
    else
        printf("该点的高度为0m");
    return 0;
}