c语言实验二

一：

#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;
}

二：

#include "stdio.h"
int main() {
    int year;
    printf("input the year:");
    scanf ("%d", &year);
    if(((year%100!=0)&&(year%4==0))||(year%400==0))
        printf("year:%d,month:2,days:29\n", year);
    else
        printf("year:%d,month:2,days:28\n", year);
    return 0;
}

三：

#include "stdio.h"
#include "math.h"
int main() {
    int a,b,c;
    scanf ("%d",&a);
    scanf ("%d",&b);
    scanf ("%d",&c);
    if ((a+b>c)&&(a+c>b)&&(b+c>a))
        if(a==b&&b==c)
            printf("等边三角形\n");
        else if(pow(a,2)+pow(b,2)==pow(c,2)||pow(a,2)+pow(c,2)==pow(b,2)||pow(c,2)+pow(b,2)==pow(a,2))
            if(a==b||a==c||b==c)
                printf("等腰直角三角形\n");
            else
                printf("直角三角形\n");
        else if(a==b||b==c||a==c)
            printf("等腰三角形\n");
        else
            printf("一般三角形\n");
    else
        printf("不是三角形\n");
    return 0;
}

四：

#include "stdio.h"
int main() {
    double a, b, rate;
    scanf("%lf", &a);
    if(a<500)
        rate=0;
    else if(a>=500&&a<1000)
        rate=0.05;
    else if(a>=1000&&a<2000)
        rate=0.08;
    else if(a>=2000&&a<5000)
        rate=0.1;
    else
        rate=0.15;
    b=rate*100;
    switch ((int)b)
    {
    case 0: printf("a=%lf   rate=%lf   tax=%lf   profit=%lf\n",a,rate,a*rate,a*(1-rate));break;
    case 5: printf("a=%lf   rate=%lf   tax=%lf   profit=%lf\n",a,rate,a*rate,a*(1-rate));break;
    case 8: printf("a=%lf   rate=%lf   tax=%lf   profit=%lf\n",a,rate,a*rate,a*(1-rate));break;
    case 10: printf("a=%lf   rate=%lf   tax=%lf   profit=%lf\n",a,rate,a*rate,a*(1-rate));break;
    case 15: printf("a=%lf   rate=%lf   tax=%lf   profit=%lf\n",a,rate,a*rate,a*(1-rate));break;
    default:printf("You wrong!\n");
    }
    return 0;
}