第五次作业

1,编写程序判断n是正数还是负数。

#include<stdio.h>

main()

{

       int n;

       printf("输入一个整数:\n");

       scanf("%d",&n);

       if(n>0)

              printf("%d是正数!\n",n);

       else

              if(n==0)

                     printf("%d既不是正数，也不是负数!\n",n);

              else

                     printf("%d是负数!\n",n);

 

}

 

 

 

 

2.使用条件运算符，找出a，b，c，d四个数中最大的数。

#include<stdio.h>

main()

{

       double a,b,c,d,m1,m2,max;

      printf("输入四个数字:\n");

       scanf("%lf%lf%lf%lf",&a,&b,&c,&d);

       m1=a>b?a:b;

       m2=c>d?c:d;

       max=m1>m2?m1:m2;

       printf("Max=%f\n",max);

}

 

 

 

 

3.已知某商场进行促销活动，对于消费的价格有折扣活动，即消费1000元，打九折；消费2000元，打8.5折，消费3000元，打7折，消费5000元，打6折。编写程序代码求出消费者实际花费的价格。

#include<stdio.h>

main()

{

       float price;

       printf("输入商品购买价格:\n");

       scanf("%f",&price);

       if(price>=5000)

              printf("实际需要支付:%.2f元\n",price*0.6);

       else if(price>=3000)

              printf("实际需要支付:%.2f元\n",price*0.7);

       else if(price>=2000)

              printf("实际需要支付:%.2f元\n",price*0.85);

       else if(price>=1000)

              printf("实际需要支付:%.2f元\n",price*0.9);

       else

              printf("实际需要支付:%.2f元\n",price);

 

}

 

 

4.输入年份,月份,判断该月有多少天

30 31 29  28

闰年:能被4整除但不能被100整除,或者能被400整除

 

#include<stdio.h>

main()

{

       int m,y,days;

       printf("请输入年和月:");

       scanf("%d%d",&y,%m);

       while(m<0//m>12//y<0)

       {

              printf("请输入正确的年份和月份!\n请重新输入正确的年月份:");

              scanf("%d%d",&y,&m);

       }

       switch(m)

       {

 

           case 1:

           case 3:

              case 5:

              case 8:

              case 10:

           case 12:days=31;break;

        case 4:

              case 6:

              case 9:

           case 11:days=30;break;

       }

       if((y%100!=0 && y%4==0)//y%400==0))

       {

              if(m==2)

              {

                     days=29;

                     printf("您输入的年份为:%d年%d月,是闰年,这个月有%d天\n",y,m,days);

              }

              else

                     printf("您输入的年份为:%d年%d月,是闰年,这个月有%d天\n",y,m,days);

       }

       else

       {

              if(m==2)

              {

                     days=28;

                     printf("您输入的年份为:%d年%d月,是平年,这个月有%d天\n",y,m,days);

              }

              else

                     printf("您输入的年份为:%d年%d月,是平年,这个月有%d天\n",y,m,days);

       }

 

 

5. 输入三条边,判断是否可以构成三角形(任意两边之和大于第三边)

 

#include<stdio.h>
main()
{
int a,b,c;
printf("请输入三边");
scanf("%d%d%d",&a,&b,&c);
if(a+b>c&&a+c>b&&b+c>a)
printf("能构成三角形");
else
printf("不能构成三角形");

}