实验2

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 5
int main()
{
int number;
int i;
srand( time(0) ); // 以当前系统时间作为随机种子
for(i = 0; i < N; ++i) {
number = rand()%65 + 1;
printf("20238331%04d\n", number);
}
system("pause:");
return 0;
}

#include <stdio.h>
#include <stdlib.h>
int main(){
	char n;
	printf("输入一个颜色\n");
	while(n=getchar()!=EOF){
	if(n=='r')
		printf("stop!\n");
	else if (n=='g')
		printf("go go go\n");
	else if (n=='y')
		printf("wait a minute\n");
	else
		printf("something must be wrong\n");
	
	getchar();
	
	
	}
	system("pause:");
	return 0;
}

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

int main()
{
int number;
int a ,b ,c , i ,n;
n = 3;
srand( time(0) ); 
number = rand()%31 + 1;
for(i=0;i<n;i++)
{scanf("%d",&a);
if(number==a)
{printf("猜中了\n");break;}
else if(number<a)
	printf("大了\n");
else if(number>a)
	printf("小了\n");

}
printf("你的幸运day是：%d\n",number);

system("pause:");
return 0;
}

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

int main()
{
int a, n ,i ;
double sum = 0,c=0;
 while(scanf("%d%d",&a,&n)!=EOF)
 {for(i=1;i<=n;i++)
 {c = 10 * c + (double)a;
 sum += i / c;
 }
 printf("sum=%lf\n", sum);
 }
system("pause:");
return 0;
}

#include <stdio.h>
#include<stdlib.h>
int main()
{
    int c, l, n;
    for (c = 1; c <= 9; c++)
    {
        for (l = 1; l <= c; l++)
        {
            n = c * l;
            printf("%dx%d =%4d  ", l, c, n);
            if (l == c)
                printf("\n");
        }
    }
    system("pause:");
    return 0;
}

#include <stdio.h>
#include<math.h>
#include<stdlib.h>
int main()
{
     int n,i,j;
   scanf("%d", &n);
    for (i=n;i>0;i--)
   {
	     
        for (j = 0; j < n - i; j++)
       {
            printf("   \t");
        }
		for (j = 0; j < (2 * i - 1); j++)
        {
            printf(" O \t");
        }
       printf("\n");
     
        for (j = 0; j < n - i; j++)
        {
            printf("   \t");
       }
        for (j = 0; j < (2 * i - 1); j++)
       {
             printf("<H>\t");
        }
       printf("\n");
       for (j = 0; j < n - i; j++)
        {
            printf("   \t");
        }
        for (j = 0; j < (2 * i - 1); j++)
        {
            printf("I I\t");
        }
        printf("\n");
         
    }
		system("pause:");
    return 0;
}