实验2 C语言分支与循环基础应用编程

#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("20238331%04d\n", number);
	}
	return 0;
}

#include <stdio.h>
int main()
{
	char sign;
	while(scanf("%c",&sign)!=EOF)
	{
		getchar();
		switch(sign)
		{
			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...\n");
				break;
		}
	}
	return 0;
}

#include<stdio.h>
#include<stdlib.h>
int main()
{
	int gett,guss=rand()%32;
	printf("Guess which day in May 2024 will be the start of your 1ucky day, you have three chances, guess (1~31):\n");
	for(int i=3;i>0;i--)
	{
		if(i<3)
			printf("Guess again (1-31):\n");
		scanf("%d",&gett);
		if(gett==guss)
			{
				printf("Wow, you got it :-)\n");
				return 0;
			}
			else if(gett<guss)
				printf("Your guess date is too early,your lucky day hasn't arrived yet. \n");
				else
				printf("Your guess date is too late,your lucky day is in front. \n");
	}
	printf("Run out of times. Please let me tell you that your lucky day in May is %d",guss);
	return 0;
}

#include<stdio.h>
#include<stdlib.h>
double dou(int x,int y)
{
	int sum=0;
	for(int i=1;i<=x;i++)
		sum=sum*10+y;
	return sum;
}
int main()
{
	int a,n;
	double s;
	while(scanf("%d%d",&n,&a)!=EOF)
	{
		s=0;
		for(int i=1;i<=n;i++)
			s=s+i/dou(i,a);
		printf("n = %d,a = %d,s = %6lf",n,a,s);
	}
	return 0;
}

#include<stdio.h>
#include<stdlib.h>
int main()
{
	for(int i=1;i<=9;i++)
	{
		for(int j=1;j<=i;j++)
			printf("%dx%d = %d ",j,i,i*j);
		printf("\n");
	}
	return 0;
}

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