随机学号生成

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

#define NUM_COUNT 5

int main() {
    srand((unsigned)time(NULL));
    for(int idx = 0; idx < NUM_COUNT; idx++) {
        int random_val = rand() % 100 + 1;
        printf("20490042%04d\n", random_val);
    }
    return 0;
}

该程序生成5个格式为"20490042XXXX"的学号，其中XXXX是1-100的随机数。srand(time(NULL))确保每次运行产生不同序列。

自动售货机模拟

#include <stdio.h>

int main() {
    int selection, qty;
    float payment, balance, current_total = 0;
    
    while(1) {
        printf("\n饮料菜单:\n");
        printf("1.可乐(3元)\n2.雪碧(3元)\n");
        printf("3.橙汁(5元)\n4.矿泉水(2元)\n0.退出\n");
        printf("请选择:");
        scanf("%d", &selection);
        
        if(selection == 0) break;
        if(selection < 1 || selection > 4) {
            printf("无效选择\n");
            continue;
        }
        
        printf("输入数量:");
        scanf("%d", &qty);
        if(qty < 0) {
            printf("数量无效\n");
            continue;
        }
        
        switch(selection) {
            case 1: case 2: current_total += 3 * qty; break;
            case 3: current_total += 5 * qty; break;
            case 4: current_total += 2 * qty; break;
        }
        
        printf("付款金额:");
        scanf("%f", &payment);
        balance = payment - current_total;
        printf("总价:%.2f\n找零:%.2f\n", current_total, balance);
        current_total = 0;
    }
    printf("感谢使用\n");
    return 0;
}

current_total=0重置交易金额，避免多次购买金额累计。continue语句在无效输入时跳过当前循环剩余部分。

交通信号模拟

#include <stdio.h>

int main() {
    char signal;
    while(scanf("%c", &signal) != EOF) {
        if(signal == '\n') continue;
        switch(signal) {
            case 'r': printf("停止!\n"); break;
            case 'g': printf("通行\n"); break;
            case 'y': printf("等待\n"); break;
            default: printf("输入错误\n");
        }
    }
    return 0;
}

消费统计程序

#include <stdio.h>

int main() {
    float expense, total = 0, max_exp, min_exp;
    printf("输入消费金额(-1结束):");
    scanf("%f", &expense);
    max_exp = min_exp = expense;
    
    while(expense != -1) {
        if(expense > 0 && expense < 20000) {
            total += expense;
            if(expense > max_exp) max_exp = expense;
            if(expense < min_exp) min_exp = expense;
        }
        scanf("%f", &expense);
    }
    printf("总消费:%.1f\n最高:%.1f\n最低:%.1f\n", total, max_exp, min_exp);
    return 0;
}

三角形类型判断

#include <stdio.h>

int main() {
    int side1, side2, side3;
    while(scanf("%d%d%d", &side1, &side2, &side3) == 3) {
        if(side1+side2>side3 && side1+side3>side2 && side2+side3>side1) {
            if(side1 == side2 && side2 == side3)
                printf("等边三角形\n");
            else if(side1==side2 || side1==side3 || side2==side3)
                printf("等腰三角形\n");
            else if(side1*side1+side2*side2==side3*side3 || 
                    side2*side2+side3*side3==side1*expense ||
                    side1*side1+side3*side3==side2*side2)
                printf("直角三角形\n");
            else
                printf("普通三角形\n");
        } else {
            printf("非三角形\n");
        }
    }
    return 0;
}

幸运日猜测游戏

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

int main() {
    int lucky_date, guess, attempts = 3;
    srand(time(0));
    lucky_date = rand() % 30 + 1;
    
    printf("猜2026年4月的幸运日(1-30):");
    while(attempts--) {
        scanf("%d", &guess);
        if(guess == lucky_date) {
            printf("猜中!\n");
            return 0;
        } 
        printf(guess > lucky_date ? "日期偏晚\n" : "日期偏早\n");
        if(attempts > 0) printf("再猜:");
    }
    printf("幸运日是%d号\n", lucky_date);
    return 0;
}

输入流处理说明

交通信号模拟中if(signal == '\n') continue;用于跳过回车符，防止将换行符作为有效输入处理。