C语言程序设计（第5版）习题解答-第4章

第4章

4. 输出三个整数中的最大值
   代码如下

#include <stdio.h>
int main()
{int a, b, c;int temp, max;printf("a = ");scanf("%d", &a);printf("b = ");scanf("%d", &b);printf("c = ");scanf("%d", &c);temp = a > b ? a : b;max = temp > c ? temp : c;printf("max = %d\n", max);return 0;
}

5. 大赛
   代码如下

#include <stdio.h>
#include <math.h>
#define MAX 1000
int main()
{int num, sqrt_num;printf("num = ");scanf("%d", &num);while (num > MAX || num < 0){printf("error, input again: \n");scanf("%d", &num);}sqrt_num = sqrt(num);printf("sqrt_num = %d\n", sqrt_num);return 0;
}

6. 程序描述分段函数
   代码如下

#include <stdio.h>
int main()
{int x, y;printf("x = ");scanf("%d", &x);if(x < 1){y  = x;printf_s("x = %3d, y = %3d\n", x, y);}else if (x < 10){y = 2 * x - 1;printf_s("x = %3d, y = %3d\n", x, y);}else{y = 3 * x - 11;printf_s("x = %3d, y = %3d\n", x, y);}return 0;
}

7. 对比两个程序
   程序代码如下

/* 代码1 */
#include <stdio.h>
int main()
{int x, y;printf_s("x = ");scanf("%d", &x);y = -1;if(x != 0){if(x > 0){y = 1;}}else{y = 0;}printf_s("y = %d\n", y);return 0;
}/* 代码2 */
int main()
{int x, y;printf_s("x = ");scanf("%d", &x);y = 0;if(x >= 0){if(x > 0){y = 1;}}else{y = -1;}printf_s("y = %d\n", y);return 0;
}

程序1不满足题目要求，输入x<0时，输出y=0；程序2不满足题目要求，输入x<0时，输出y=0。

8. 对成绩进行分级
   代码如下

#include <stdio.h>
int main()
{float score;char grade;printf("score = ");scanf("%f", &score);while (score < 0 || score > 100){printf("error, input again: \n");scanf("%f", &score);}switch((int)(score / 10)){case 10:case 9:grade = 'A';break;case 8:grade = 'B';break;case 7:grade = 'C';break;case 6:grade = 'D';break;default:grade = 'E';break;}printf("grade = %c\n", grade);return 0;
}

9. 判断数据
   代码如下

int main()
{int num, num_place;int num_1, num_2, num_3, num_4, num_5;printf_s("num = ");scanf("%d", &num);if(num > 9999){num_place = 5;}else if(num > 999){num_place = 4;}else if(num > 99){num_place = 3;}else if(num > 9){num_place = 2;}else{num_place = 1;}num_1 = num % 10;num_2 = num % 100 / 10;num_3 = num % 1000 / 100;num_4 = num % 10000 / 1000;num_5 = num / 10000;printf("num_1 = %d\n", num_1);printf("num_2 = %d\n", num_2);printf("num_3 = %d\n", num_3);printf("num_4 = %d\n", num_4);printf("num_5 = %d\n", num_5);printf("num_place = %d\n", num_place);switch(num_place){case 5:printf("%d, %d, %d, %d, %d\n", num_5, num_4, num_3, num_2, num_1);printf_s("\n reverse order: ");printf("%d, %d, %d, %d, %d\n", num_1, num_2, num_3, num_4, num_5);break;case 4:printf("%d, %d, %d, %d\n", num_4, num_3, num_2, num_1);printf_s("\n reverse order: ");printf("%d, %d, %d, %d\n", num_1, num_2, num_3, num_4);break;case 3:printf("%d, %d, %d\n", num_3, num_2, num_1);printf_s("\n reverse order: ");printf("%d, %d, %d\n", num_1, num_2, num_3);break;case 2:printf("%d, %d\n", num_2, num_1);printf_s("\n reverse order: ");printf("%d, %d\n", num_1, num_2);break;case 1:printf("%d\n", num_1);printf_s("\n reverse order: ");printf("%d\n", num_1);break;default:break;}return 0;
}

10. 企业发放奖金提成
    代码如下

// if语句
double get_bonus_if(int profit)
{double bonus, bon1, bon2, bon4, bon6, bon10;bon1 = 100000 * 0.1;bon2 = bon1 + 100000 * 0.075;bon4 = bon2 + 100000 * 0.05;bon6 = bon4 + 100000 * 0.03;bon10 = bon6 + 400000 * 0.015;if (profit <= 100000){bonus = profit * 0.1;}else if (profit <= 200000){bonus = bon1 + (profit - 100000) * 0.075;}else if (profit <= 400000){bonus = bon2 + (profit - 200000) * 0.05;}else if (profit <= 600000){bonus = bon4 + (profit - 400000) * 0.03;}else if (profit <= 1000000){bonus = bon6 + (profit - 600000) * 0.015;}else{bonus = bon10 + (profit - 1000000) * 0.01;}return bonus;
}// switch语句
double get_bonus_switch(int profit)
{double bonus;int branch = profit / 100000;if (branch > 10)branch = 10;switch (branch){case 0:bonus = profit * 0.1;break;case 1:bonus = 100000 * 0.1 + (profit - 100000) * 0.075;break;case 3:bonus = 100000 * 0.1 + 100000 * 0.075 + (profit - 200000) * 0.05;break;case 5:bonus = 100000 * 0.1 + 100000 * 0.075 + 200000 * 0.05 + (profit - 400000) * 0.03;break;case 9:bonus = 100000 * 0.1 + 100000 * 0.075 + 200000 * 0.05 + 200000 * 0.03 + (profit - 600000) * 0.015;break;case 10:bonus = 100000 * 0.1 + 100000 * 0.075 + 200000 * 0.05 + 200000 * 0.03 + 400000 * 0.015 + (profit - 1000000) * 0.01;break;}return bonus;
}
#include "funcs.h"int main()
{printf_s("the bonus is:%.2f\n", get_bonus_if(234000));printf_s("the bonus is:%.2f\n", get_bonus_switch(234000));return 0;
}

11. 四个整数排序
    代码如下

// 采用依次比较法
void sort_fornums(int a, int b, int c, int d)
{int temp;if (a > b){temp = a;a = b;b = temp;}if (c > d){temp = c;c = d;d = temp;}if (a > c){temp = a;a = c;c = temp;}if (b > d){temp = b;b = d;d = temp;}if (b > c){temp = b;b = c;c = temp;}printf("%d %d %d %d\n", a, b, c, d);
}

12. 求建筑高度
    代码如下

// 根据该点到圆心的距离进行判断
int get_height(int x, int y)
{int x1 = 2, y1 = 2, x2 = -2, y2 = 2, x3 = 2, y3 = -2, x4 = -2, y4 = -2;float d1, d2, d3, d4;d1 = (x - x1) * (x - x1) + (y - y1) * (y - y1);d2 = (x - x2) * (x - x2) + (y - y2) * (y - y2);d3 = (x - x3) * (x - x3) + (y - y3) * (y - y3);d4 = (x - x4) * (x - x4) + (y - y4) * (y - y4);if (d1 > 1 && d2 > 1 && d3 > 1 && d4 > 1){return 0;}else{return 10;}
}