实验2
1、实验任务1
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <time.h> 4 5 #define N 5 6 7 int main() { 8 int number; 9 int i; 10 11 srand(time(0)); // 以当前系统时间作为随机种子 12 for(i = 0; i < N; ++i) { 13 number = rand() % 100 + 1; 14 printf("20490042%04d\n", number); 15 } 16 17 return 0; 18 }
问题1:line13代码的功能是生成一个1~100的随机整数
问题2:%04d的作用是输出一个4位随机数
问题3:程序的功能是生成一个12位的学员编号,其中前九位为204900420,后三位为000~100随机数
2、实验任务2
1 #include <stdio.h> 2 3 int main() { 4 int choice, quantity; 5 float total_price = 0, amount_paid, change; 6 7 while (1) { 8 printf("\n自动饮料售卖机菜单:\n"); 9 printf("1. 可乐 - 3 元/瓶\n"); 10 printf("2. 雪碧 - 3 元/瓶\n"); 11 printf("3. 橙汁 - 5 元/瓶\n"); 12 printf("4. 矿泉水 - 2 元/瓶\n"); 13 printf("0. 退出购买流程\n"); 14 printf("请输入饮料编号: "); 15 scanf("%d", &choice); 16 17 if (choice == 0) 18 break; 19 20 if (choice < 1 || choice > 4) { 21 printf("无效的饮料编号,请重新输入。\n"); 22 continue; 23 } 24 25 printf("请输入购买的数量: "); 26 scanf("%d", &quantity); 27 28 if (quantity < 0) { 29 printf("购买数量不能为负数,请重新输入。\n"); 30 continue; 31 } 32 33 switch (choice) { 34 case 1: 35 case 2: 36 total_price += 3 * quantity; 37 break; 38 case 3: 39 total_price += 5 * quantity; 40 break; 41 case 4: 42 total_price += 2 * quantity; 43 break; 44 } 45 46 printf("请投入金额: "); 47 scanf("%f", &amount_paid); 48 49 change = amount_paid - total_price; 50 printf("本次购买总价: %.2f 元\n", total_price); 51 printf("找零: %.2f 元\n", change); 52 53 total_price = 0; 54 } 55 56 printf("感谢您的购买,欢迎下次光临!\n"); 57 return 0; 58 }
问题1:line53代码起到重置总价的作用,去掉会导致后续总价计算出现错误
问题2:break语句会完全退出循环,而continue只是跳过当前迭代,不会退出循环
问题3:没有必要,因为case已经完全覆盖了所有可能的情况
3、实验任务3
1 #define _CRT_SECURE_NO_WARNINGS 2 #include<stdio.h> 3 4 int main() { 5 char x; 6 while ((x=getchar())!=EOF) { 7 getchar(); 8 switch (x) { 9 case'r': 10 printf("stop!\n"); 11 break; 12 case'g': 13 printf("go go go\n"); 14 break; 15 case'y': 16 printf("wait a minute\n"); 17 break; 18 default: 19 printf("somthing must be wrong...\n"); 20 break; 21 } 22 } 23 return 0; 24 }
4、实验任务4
1 #define _CRT_SECURE_NO_WARNINGS 2 #include<stdio.h> 3 4 int main() { 5 float x,max=0,min=20000,total=0; 6 printf("输入今日开销,直到输入-1终止:"); 7 while (1) { 8 scanf("%f", &x); 9 if (x == -1) 10 break; 11 if (x > max) 12 max = x; 13 if (x < min) 14 min = x; 15 total += x; 16 } 17 printf("今日累计消费总额:%.1f\n", total); 18 printf("今日最高一笔开销:%.1f\n", max); 19 printf("今日最低一笔开销:%.1f\n", min); 20 return 0; 21 }
5、实验任务5
1 #define _CRT_SECURE_NO_WARNINGS 2 #include<stdio.h> 3 #include<stdlib.h> 4 #include<time.h> 5 6 int main() { 7 printf("猜猜2025年4月哪一天是你的lucky day\n"); 8 int x, a, n=0; 9 srand(time(0)); 10 a = rand() % 30 + 1; 11 printf("开始喽,你有三次机会,猜吧(1—30):"); 12 while (n < 3) { 13 scanf("%d",&x); 14 n += 1; 15 if (x == a){ 16 printf("哇,猜中了\n"); 17 return 0; 18 } 19 else if (x < a) { 20 printf("你猜的日期早了,你的lucky day还没到呢\n"); 21 } 22 else { 23 printf("你猜的日期晚了,你的lucky day在前面哦\n"); 24 } 25 if (n < 3) 26 printf("再猜(1-30):\n"); 27 } 28 printf("次数用完啦,偷偷告诉你,4月你的lucky day是%d号\n", a); 29 return 0; 30 }
6、实验任务6
1 #define _CRT_SECURE_NO_WARNINGS 2 #include<stdio.h> 3 4 void xiaoren(int line) { 5 switch (line) { 6 case 0: 7 printf(" 0 "); 8 break; 9 case 1: 10 printf(" <H> "); 11 break; 12 case 2: 13 printf(" I I "); 14 break; 15 } 16 } 17 int main() { 18 int n; 19 printf("input n:"); 20 scanf("%d", &n); 21 22 for (int i = n; i > 0; i--) { 23 int x = 2 * i - 1; 24 int kg = (n - i) * 7; 25 for (int j = 0; j < kg; j++) { 26 printf(" "); 27 } 28 for (int hang = 0; hang < 3; hang++) { 29 for (int j = 0; j < x; j++) { 30 xiaoren(hang); 31 } 32 printf("\n"); 33 34 for (int j = 0; j < kg; j++) { 35 printf(" "); 36 } 37 } 38 printf("\n"); 39 } 40 return 0; 41 }