实验二 选择结构程序设计

#include<stdio.h>
int main()
{
    char a,b,c,d,e;
    a=getchar();
    b=getchar();
    c=getchar();
    d=getchar();
    e=getchar();
    putchar(a);
    putchar(b);
    putchar(c);
    putchar(d);
    putchar(e);
    return 0;
}

#include<stdio.h>
int main()
{
    int year;
    printf("请输入一个年份：");
    scanf("%d",&year);
    if(year%4 == 0||(year%400==0&&year%100 !=0))
    {
        printf("%d年2月有29天\n",year);
    }
    else
        printf("%d年2月有28天\n",year);
    return 0;
}

#include"stdio.h"
#include<math.h>
int main()
{
    int a,b,c;
    printf("请输入三角形的三边：");
    scanf("%d%d%d",&a,&b,&c);
    if((a+b)>c&&(b+c)>a&&(c+a)>b)
    {
        if(a==b&&b==c&&a==c)
            printf("全等三角形");
        else if(a==b||b==c||a==c)
            printf("等腰三角形");
        else if((pow(a,2)+pow(b,2))==pow(c,2)||(pow(c,2)+pow(b,2))==pow(a,2)||(pow(a,2)+pow(c,2))==pow(b,2))
            printf("直角三角形");
        else if(1)
            printf("一般三角形");
    }
    else
        printf("不能构成三角形");
    return 0;
}

#include<stdio.h>
#include<math.h>
int main()
{
    double a,rate,tax,profit;
    scanf("%lf",&a);
    if(a>=5000)
        rate = 0.15;
    else if(a >= 2000)
        rate = 0.10;
    else if(a >= 1000)
        rate = 0.08;
    else if(a >= 500)
        rate = 0.05;
    else if(a < 500)
    rate = 0;
    tax = a - (a*rate);
    profit = a - tax;
    printf("a = %lf \nrate=%lf \ntax=%lf \nprofit=%lf\n",a,rate,tax,profit);
    return 0;
}

#include<stdio.h>
#include<math.h>
int main()
{
    double a,rate,tax,profit;
    int b;
    scanf("%lf",&a);
    b = a/500;
    switch(b){
    case 0: rate = 0.00; break;
    case 1: rate = 0.05; break;
    case 2: rate = 0.08; break;
    case 3: rate = 0.08; break;
    case 4: rate = 0.10; break;
    case 5: rate = 0.10; break;
    case 6: rate = 0.10; break;
    case 7: rate = 0.10; break;
    case 8: rate = 0.10; break;
    case 9: rate = 0.10; break;
    default: rate = 0.15;
    }
    tax = a - (a*rate);
    profit = a - tax;
    printf("a = %lf \nrate=%lf \ntax=%lf \nprofit=%lf\n",a,rate,tax,profit);
    return 0;
}