实验2

`#include <stdio.h>

include<stdlib.h>

include<time.h>

define N 5

define N1 80

define N2 35

int main()
{
int cnt;
int random_major, random_no;

srand(time(NULL));

cnt = 0;
while (cnt < N) {
    random_major = rand() % 2;

    if (random_major) {
        random_no = rand() % N1 + 1;
        printf("20256343%04d\n", random_no);
    }
    else {
        random_no = rand() % N2 + 1;
        printf("20256236%04d\n", random_no);
    }

    cnt++;
    return 0;
}

}`

作用：生成一个随机的学号
功能：每一次运行都能生成不同的学号，删除这一行侯多次运行只能生成第一次的运行结果。

`#define _CRT_SECURE_NO_WARNINGS

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\n", change);

    total_price = 0;
}
printf("感谢您的购买，欢迎下次光临！\n");

return 0;

}`

影响：这次购买的金额会和上次购买的金额累加
1.这次输入的饮料编号不存在，回到输入饮料编号的地方。
2.回到输入购买数量的地方。

`#include<stdio.h>
int main() {
char ch;

while (scanf_s(" %c",&ch) != EOF) {


	if (ch == 'r') {
		printf("stop!\n", ch);
		continue;
	}

	else if (ch == 'g') {

		printf("go,go,go\n", ch);
		continue;
	}
	else if (ch == 'y') {
		printf("wait a minute\n", ch);
		continue;
	}
	else {
		printf("something must be wrong...\n", ch);
		continue;
	}
}
return 0;

}`

`#include<stdio.h>

int main() {
double mum, max, min, sum;
sum = 0.0;
max = 0.0;
min = 20000.0;
printf("输入今日总开销：\n");

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

	if (mum <= 0.0 || mum >20000.0) {
		continue;
	}
	sum += mum;
	if (mum > max) {
		max = mum;
	}
	if (mum < min) {
		min = mum;
	}
	
}
printf("今日总开销金额：%.1f\n", sum);
printf("今日最高一笔开销：%.1f\n", max);
printf("今日最低一笔开销：%.1f\n", min);

return 0;

}
`

`#include<stdio.h>

int main(){
int a,b,c;
scanf_s("%d%d%d", &a, &b,&c);

while (scanf_s("%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");
		continue;
	}
					
	if (a == b&&b == c) {
		printf("等边三角形\n");
	}
	else if (a == b || a == c || b == c) {
		printf("等腰三角形\n");
	}
	else if (a* a == b * b + c * c || b * b == a * a + c * c || c * c == a * a + b * b) {
		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 a, b, c = 3;
	srand((unsigned int)time(NULL));
a = rand() % 30 + 1;
printf("猜一猜2025年11月哪一天是你的luckyday\n");

while (c > 0) {
	printf("开始喽，你有%d次机会，猜吧（1~30）：", c);
	scanf_s("%d", &b);
	if (b == a) {
		printf("猜中了\n");
		return 0;
	}
	else if (b > a) {
		printf("你猜的日期晚了，你的luckyday在前面哦");
	}
	else {
		printf("你猜的日期早了，你的luckyday在后面哦");
	}
	c--;
	if (c > 0) {
		printf("再猜一次吧：");
	}
}
printf("次数用光了，偷偷告诉你，11月你的luckyday是%d号\n", a);

return 0;

}
`