实验2 格式化输入输出和分支语句

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

int main()
{
    int x = 1234;
    float f = 123.456;
    double m = 123.456;
    char ch = ‘a‘;
    char a[] = "Hello, world!"; // 定义一个数组a,数组中连续存放了字符串常量hello,world!
    int y = 3, z = 4;
    printf("%d %d\n", y, z);
    printf("y=%d, z=%d\n", y, z);
    printf("%8d,%2d\n", x, x);
    printf("%f, %8f, %8.1f, %0.2f, %.2e\n", f, f, f, f, f);
    printf("%lf\n", m);
    printf("%3c\n", ch);
    printf("%s\n%15s\n%10.5s\n%2.5s\n%.3s\n", a, a, a, a, a);

    system("pause");
    return 0;
}

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

int main()
{
    double x, y;
    char c1, c2, c3;
    int a1, a2, a3;
    scanf_s("%d%d%d", a1, a2, a3);          //少&
    printf("%d,%d,%d\n", a1, a2, a3);
    scanf_s("%c%c%c", &c1, &c2, &c3);
    printf("%c%c%c\n", c1, c2, c3);
    scanf_s("%f,%lf", &x, &y);              //double类型用%lf
    printf("%f,%lf\n", x, y);

    system("pause");
    return 0;
}

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

int main()
{
    double a, b, c;
    scanf_s("%lf %lf %lf", &a, &b, &c);
    if (a<0 || b<0 || c < 0)
        printf("不能构成三角形\n");
    else if (a + b > c && a + c>b && b + c>a) {
        if (a == b && a == c)
            printf("构成等边三角形\n");
        else if (a == b || a == c || b == c)
            printf("构成等腰三角形\n");
        else
            printf("构成一般三角形\n");
    }
    else
        printf("不能构成三角形\n");
    system("pause");
    return 0;
}

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

int main()
{
    char choice;
    // 显示菜单
    printf("输入0~9以内的数字，选择屏幕背景色前景色方案: \n");
    printf("1-\t黑底绿色\n");
    printf("2-\t白底黑色\n");
    printf("3-\t蓝底白色\n");
    printf("其它-\t黑底白色(默认)\n");
    printf("\n请输入, 选择你想使用的屏幕配色方案: ");
    // 要求用户从键盘输入0~9的数字，选择屏幕配色方案
    choice = getchar();
    // 根据用户输入，设置屏幕配色方案
    if (choice == ‘1‘) {
        system("color 02");
        printf("《黑客帝国》一类的影视剧常见这种屏幕色:)\n");
    }
    else if (choice == ‘2‘) {
        system("color f0");
        printf("大部分编辑器默认是这种配色:)\n");
    }
    else if (choice == ‘3‘) {
        system("color 1f");
        printf("这是机器蓝屏故障时的不讨喜色:)\n");
    }
    else{
        system("color 0f");
        printf("控制台程序默认小黑窗:)\n");
    }
    printf("programming is fun, just try@_@\n");

    system("pause");
    return 0;
}

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

int main()
{
    int length, flag = 1;
    char a[100];
    gets_s(a);
    length = strlen(a);

    for (int i = 0; i <= length / 2; i++)
    {
        if (a[i] != a[length - i - 1])
        {
            flag = 0;
            break;
        }
    }
    if (flag == 1)
        printf("正序和逆序相同\n");
    else
        printf("正序和逆序不同\n");

    system("pause");
    return 0;
}

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

int main()
{
    int year, month, day, leapyear;
    scanf_s("%d%d", &year, &month);
    if (year<0||month<1||month>12)
    {
        printf("输入的数据错误\n");
        exit(0);
    }
    leapyear = year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
    if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12)
        day = 31;
    else if (month == 4 || month == 6 || month == 9 || month == 11)
        day = 30;
    else
        day = 28 + leapyear;

    printf("%d年%d月的天数为：%d\n", year, month, day);
    
    system("pause");
    return 0;
}

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

int main()
{
    int score;
    printf("输入分数（0~100）:");
    scanf_s("%d", &score);
    if (score < 0 || score>100)
    {
        printf("输入数据错误\n");
        exit(0);
    }
    switch (score / 10)
    {
        case 10:
        case 9: printf("优秀\n"); break;
        case 8: printf("良好\n"); break;
        case 7: printf("中等\n"); break;
        case 6: printf("及格\n"); break;
        default: printf("不及格\n"); break;
    }
    
    system("pause");
    return 0;
}