实验2

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

#define N 5

int main(){
	int number;
	int i;
	
	srand( time(0));
	
	for(i=0;i<N;++i){
		number=rand()%65+1;
		printf("2023833%04d\n",number);
	}
	return 0;
} 

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

int main(){
	char n;
	while(scanf("%c",&n)!=EOF)
	{
	switch(n)
	{
		case'r':printf("stop\n");break;
		case'g':printf("go go go\n");break;
		case'y':printf("wait a minute\n");break;
		default:printf("something must be wrong……");break;
	}
	getchar();
    }
	return 0;
}

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

int main()
{
	int luckyday,guess;
	int n=0;
	
	srand(time(0));
	luckyday=rand()%31+1;
	
	printf("猜猜2024年5月哪一天会是你的lucky day\n\n");
	printf("开始喽，你有三次机会，猜吧（1~31）:");
	
	while(n<3)
	{
		scanf("%d",&guess);
		
		if(guess==luckyday)
		{
			printf("哇，猜中了:-)\n");
		}
		else if(guess<luckyday)
		{
			printf("你猜的日期早了，你的lucky day还没到呢\n");
		}
		else
		{
			printf("你猜的日期晚了，你的lucky day在前面哦\n");
		}
		if(n<2)
		{
			printf("\n再猜（1~31):");
		}
		n++;
	}
	if(n==3)
	{
		printf("\n\n次数用完了，偷偷告诉你，5月你的lucky day是%d号\n",luckyday);
	}
	return 0;
 } 

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

int main() {
    int n, a, i, j, m=0;
    double s = 0.0;

    while (scanf("%d%d", &n, &a) != EOF) {
        s = 0.0;
        for (i = 1; i <= n; i++) {
            m=0;
            for (j = 0; j < i; j++) {
                m = m * 10 + 1;
            }
            s += (double)i / (a * m);
        }

        printf("n = %d, a = %d, s = %lf\n\n", n, a, s);
    }
    system("pause");
    return 0;
}

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

int main() {
    int i, j;

    for (i = 1; i <= 9; i++)
    {
        for (j = 1; j <= i; j++)
        {
            printf("%d×%d =%2d\t", j, i, i * j);
        }
        printf("\n");
    }
    system("pause");
    return 0;
}

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

int main() {
	int n, i, k, j;
	printf("input n:");
	scanf("%d", &n);

	for (i = 0; i < n; i++)
	{
		for (j = 0; j < i; j++)
		{
			printf("\t");
		}
		for (k = 2 * (n-i) - 1; k>0; k--)
		{
			printf(" O \t");
		}
		printf("\n");

			for (j = 0; j < i; j++)
			{
				printf("\t");
		}
		for (k = 2 * (n-i) - 1; k>0; k--) {
			printf("<H>\t");
		}
		printf("\n");

		for (j = 0; j < i; j++)
		{
			printf("\t");
		}
		for (k = 2 * (n - i) - 1; k > 0; k--)
		{
			printf("I I\t");
		}
		printf("\n");
	}
	return 0;
}