实验二

试验任务一

 源代码

#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("20490042%04d\n", number);
}
system("pause");
return 0;
}

运行结果截图

 问题

1.生成5个范围在1~100之间的随机整数，并按指定格式输出这些随机数

2.生成一个1~100的随机整数，并赋值给number

3.确保输出时，20490042后有四位数

4.使生成的数是随机的，而不是多次运行后结果一样

试验任务二

源代码

#include <stdio.h>
#include<stdlib.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;
}
if(choice == 1 || choice == 2)
total_price += 3 * quantity;
else if(choice == 3)
total_price += 5 * quantity;
else
total_price += 2 * quantity;
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");
system("pause");
return 0;
}

 

运行结果截图

 

 问题

1.会记入上一次购买总价，导致这一次的输出结果有问题

2.跳过循环体内后续的代码，直到返回循环条件判断处，开始下一次循环

试验任务三

源代码

#include<stdio.h>
#include<stdlib.h>
int main(){
char c;
while(scanf("%c",&c) != EOF){
if (c == '\n')
continue;
if (c == 'r'){
printf("stop!\n");
}
else if (c == 'g'){
printf("go go go\n");
}
else if (c == 'y'){
printf("wait a mintue\n");
}
else{
printf("something must be wrong...\n");
}
}
system("pause");
return 0;
}

运行结果截图

 

试验任务四

源代码

#include <stdio.h>
#include<stdlib.h>
int main() {
double expense;
double total = 0.0;
double max_exp =0.0;
double min_exp =20000;
int count = 0;
printf("输入今日开销，直到输入-1终止:\n");
while (1) {
scanf("%lf", &expense);
if (expense == -1) {
break;
}
if (expense <= 0 || expense > 20000) {
printf("输入无效，请输入0~20000之间的金额，或-1终止\n");
continue;
}
total += expense;
count++;
if (expense > max_exp) {
max_exp = expense;
}
if (expense < min_exp) {
min_exp = expense;
}
}
if (count == 0) {
printf("无有效开销记录\n");
}else {
printf("今日累计消费总额: %.1f\n", total);
printf("今日最高一笔开销: %.1f\n", max_exp);
printf("今日最低一笔开销: %.1f\n", min_exp);
}
system("pause");
return 0;
}

 

运行结果截图

 

 

试验任务五

源代码

#include <stdio.h>
#include<stdlib.h>
int main()
{
int a, b, c;
printf("请输入三角形三边边长（整数），输入结束按 CTRL+Z：\n");
while (scanf("%d %d %d", &a, &b, &c) != EOF)
{
if (a + b <= c || a + c <= b || b + c <= a)
{
printf("不能构成三角形\n");
continue;
}
if (a * a + b * b == c * c || a * a + c * c == b * b || b * b + c * c == a * a)
{
printf("直角三角形\n");
continue;
}
if (a == b && b == c)
{
printf("等边三角形\n");
continue;
}
if (a == b || a == c || b == c)
{
printf("等腰三角形\n");
continue;
}
printf("普通三角形\n");
}
system("pause");
return 0;
}

 

运行结果截图

 

试验任务六

源代码

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main()
{
int luckyDay, guess;
int attempt;
srand((unsigned int)time(NULL));
luckyDay = rand() % 30 + 1;
printf("猜猜2026年4月哪一天是你的lucky day\n");
printf("开始喽，你有3次机会，请猜(1-30)：");
for (attempt = 1; attempt <= 3; attempt++)
{
scanf("%d", &guess);
if (guess == luckyDay)
{
printf("哇，猜中了！\n");
system("pause");
return 0;
}
else if (guess < luckyDay)
{
printf("你猜的日期早了，你的lucky day还没到呢\n");
}
else
{
printf("你猜的日期晚了，你的lucky day在前面哦\n");
}
if (attempt < 3)
{
printf("再猜(1-30)：");
}
}
printf("次数用光啦。4月的lucky day是%d号\n", luckyDay);
system("pause");
return 0;
}

运行结果截图