实验2

#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);
}
return 0;
}

#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;
}
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");
return 0;
}

#include <stdio.h>

int main() {
char ch;

while (scanf("%c", &ch) != EOF) {
if (ch == 'r') {
printf("stop!\n");
} else if (ch == 'g') {
printf("go go go\n");
} else if (ch == 'y') {
printf("wait a minute\n");
} else {

if (ch != '\n') {
printf("something must be wrong...\n");
}
}
}
return 0;

}

#include <stdio.h>

int main() {
    double expense;
    double total = 0.0;
    double max_expense = 0.0;
    double min_expense = 20000.0; 
    int count = 0;

    printf("输入今日开销，直到输入-1终止：\n");

   
    while (scanf("%lf", &expense) == 1) {
        if (expense == -1) {
            break; 
        }

      
        if (expense <= 0 || expense > 20000) {
            printf("输入无效！请输入0到20000之间的数值（输入-1终止）\n");
            continue;
        }

      
        total += expense;
        count++;

      
        if (expense > max_expense) {
            max_expense = expense;
        }

        if (expense < min_expense) {
            min_expense = expense;
        }
    }

    if (count > 0) {
        printf("今日累计消费总额：%.1f\n", total);
        printf("今日最高一笔开销：%.1f\n", max_expense);
        printf("今日最低一笔开销：%.1f\n", min_expense);
    } else {
        printf("未输入有效开销！\n");
    }

    return 0;
}

#include <stdio.h>

void swap(int *x, int *y) {
int temp = *x;
*x = *y;
*y = temp;
}

int main() {
int a, b, c;
while (scanf("%d%d%d", &a, &b, &c) != EOF) {
if (a > b) swap(&a, &b);
if (b > c) swap(&b, &c);
if (a > b) swap(&a, &b);

if (a + b <= c) {
printf("不能构成三角形\n");
continue;
}

if (a == b && b == c) {
printf("等边三角形\n");
}
else if (a == b || b == c || a == c) {
printf("等腰三角形\n");
}
else if (a * a + b * b == c * c) {
printf("直角三角形\n");
}
else {
printf("普通三角形\n");

}
}
return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main() {
int lucky_day, guess;
int chance = 3;

srand((unsigned int)time(NULL));
lucky_day = rand() % 30 + 1;

printf("猜猜2026年4月哪一天是你的lucky day\n");

while (chance > 0) {
printf("开始喽，你有%d次机会，猜吧(1~30): ", chance);
scanf("%d", &guess);

if (guess == lucky_day) {
printf("哇，猜中了:)\n");
return 0;
} else if (guess > lucky_day) {
printf("你猜的日期晚了，你的lucky day在前面哦\n");
} else {
printf("你猜的日期早了，你的lucky day还没到呢\n");
}

chance--;
if (chance > 0) {
printf("再猜(1~30): ");
scanf("%d", &guess);

if (guess == lucky_day) {
printf("哇，猜中了:)\n");
return 0;
} else if (guess > lucky_day) {
printf("你猜的日期晚了，你的lucky day在前面哦\n");
} else {
printf("你猜的日期早了，你的lucky day还没到呢\n");
}

chance--;
if (chance > 0) {
printf("再猜(1~30): ");
scanf("%d", &guess);

if (guess == lucky_day) {
printf("哇，猜中了:)\n");
return 0;
} else if (guess > lucky_day) {
printf("你猜的日期晚了，你的lucky day在前面哦\n");
} else {
printf("你猜的日期早了，你的lucky day还没到呢\n");
}

chance--;
}
}
}

printf("次数用光啦。4月你的lucky day是%d号\n", lucky_day);
return 0;
}

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