实验2
TEST1
代码：
`
include <stdio.h>
include <stdlib.h>
include <time.h>
define N 5
int main()
{
int number;
int i;
srand(time(0));
for(i=0;i<N;++i){
number = rand()%100+1;
printf("20290042%04d\n",number);
system("pause");
}
return 0;
}
`
问题1：生成1个1到100的随机数
问题2：使生产的随机数均占4格，不足用0补
问题3：随机生成5个在202400420001到202400420100之间的学号
截图：
TEST2
代码：
`
include <stdio.h>
int main() {
int choice, quantity;
float total_price = 0, amount_paid, change;
while (1) {
printf("\n自动饮料售卖机菜单:\n");
printf("1. 可乐 - 3 元/瓶\n");
printf("2. 雪碧 - 3 元/瓶\n");
printf("3. 橙汁 - 5 元/瓶\n");
printf("4. 矿泉水 - 2 元/瓶\n");
printf("0. 退出购买流程\n");
printf("请输入饮料编号: ");
scanf("%d", &choice);
if (choice == 0)
break;
if (choice < 1 || choice > 4) {
printf("无效的饮料编号，请重新输入。\n");
continue;
}
printf("请输入购买的数量: ");
scanf("%d", &quantity);
if (quantity < 0) {
printf("购买数量不能为负数，请重新输入。\n");
continue;
}
switch (choice) {
case 1:
case 2:
total_price += 3 * quantity;
break;
case 3:
total_price += 5 * quantity;
break;
case 4:
total_price += 2 * quantity;
break;
}
printf("请投入金额: ");
scanf("%f", &amount_paid);
change = amount_paid - total_price;
printf("本次购买总价: %.2f 元\n", total_price);
printf("找零: %.2f 元\n", change);
total_price = 0;
}
printf("感谢您的购买，欢迎下次光临！\n");
return 0;
}
`
问题1：将total_price重新赋值为0，去掉则下一次循环的总价会与上一次总价叠加
问题2：break为跳出当前循环结构；continue为跳出本次循环，进入下一循环
问题3：没必要，因该switch语句已涵盖全部情况
截图：
TEST3
代码：
`
include <stdio.h>
include <stdlib.h>
int main()
{
char deng;
while (1)
{
scanf("%c", &deng);
if (deng != 'r' && deng != 'g' && deng != 'y') {
deng = getchar();
printf("something is wrong\n");
continue;
}
switch (deng)
{
case 'r': printf("stop!\n"); break;
case 'y': printf("wait a minute\n"); break;
case 'g': printf("go go go\n"); break;
}
deng = getchar();
}
return 0;
}
`
截图：
TEST4
代码：
`
include <stdio.h>
include <stdlib.h>
int main()
{
double max, min, n, s = 0.0;
printf("输入今日开销，直到输入-1终止：\n");
max = 0;
min = 20000;
do {
scanf("%lf", &n);
if (n <= 0 || n > 20000) {
break;
}
if (max <= n) {
max = n;
}
if (min >= n) {
min = n;
}
s = s + n;
} while (n != -1);
printf("今日累计消费：%.1f\n", s);
printf("今日最高一笔开销：%.1f\n", max);
printf("今日最低一笔开销：%.1f\n", min);
system("pause");
return 0;
}
`
截图：
TEST5
代码：
`
include <stdio.h>
include <stdlib.h>
include <time.h>
int main()
{
int number ,a=1;
int i;
srand(time(0));
number = rand() % 30 + 1;
printf("猜猜2025年4月那一天是你的lucky day\n开始喽，你有三次机会，猜吧（1~30）😊;
while (scanf("%d", &i) != EOF) {
if (i > number) {
printf("你猜的日期晚了，你的lucky day在前面哦\n再猜:");
}
else if (i < number) {
printf("你猜的日期早了，你的lucky day还没到呢\n再猜:");
}
else
printf("哇！猜中了");
a = a + 1;
if(a>3){
printf("此时用完啦，偷偷告诉你，是%d号\n",number);
break;
}
}
return 0;
}
`
截图：
TEST6
代码：
`
include <stdio.h>
include <stdlib.h>
int main() {
int n, i, j, k;
printf("input n:");
scanf("%d", &n);
for (j = 0; n >= 1; --n)
{
for (k = j; k > 0; --k)
printf("\t");
for (i = 2 * n - 1; i != 0; --i)
printf(" O\t");
printf("\n");
for (k = j; k > 0; --k)
printf("\t");
for (i = 2 * n - 1; i != 0; --i)
printf("<H>\t");
printf("\n");
for (k = j; k > 0; --k)
printf("\t");
for (i = 2 * n - 1; i != 0; --i)
printf("I I\t");
printf("\n");
++j;
}
system("pause");
return 0;
}
`
截图：
