C language

for循环

#include <stdio.h>
int main()
{
	for(double value=36;value>0;value/=2)
	printf("%3d",value);
	return 0;
}

打开文件

#include <stdio.h>
int main(void)
{
	char line[10];
	FILE* source_file=fopen("test_01.c","r");
	char* end;
	if(!source_file)
	{
		printf("Opne fali!");
		return 0;
	}
	while(1)
	{
	end=fgets(line,sizeof(line),source_file);
	if(end)
	{
	 printf("%s",line);
	}
	else break;
	}

	return 0;
}

斐波那契数列

#include<stdio.h>
int main(void){		//实现斐波那契数列---2019.7.20
	int arr_length=0;
	int i_1=1,i_2=1,i_3=2;
	int i=0;
	printf("Input a array length\n");
	scanf("%d",&arr_length);
	if(arr_length==3)
		printf("%d %d %d\n",i_1,i_2,i_3);
	if(arr_length==2)
		printf("%d %d\n",i_1,i_2);
	if(arr_length==1)
		printf("%d\n",i_1);
	if(arr_length>=4)
	{	
		printf("%d %d %d",i_1,i_2,i_3);
		while(i<(arr_length-3))
		{
			i_1=i_2;
			i_2=i_3;
			i_3=i_1+i_2;
			printf(" %d",i_3);
			i++;
		}
		printf("\n");
	}
	if(arr_length<=0)
	printf("There is a error!\n");
	return 0;
}

金字塔

#include <stdio.h>	//print Jin TA
void Print(int line,char sign){
	for(int i_1=line;i_1>0;i_1--)
	{
		for(int i_2=0;i_2<(i_1-1);i_2++)
			printf(" ");
		for(int i_3=0;i_3<(2*(line-i_1+1)-1);i_3++)
			printf("%c",sign);
		printf("\n");
	}
}
int main(){
	Print(25,'$');
	return 0;
}

汉罗塔攻略

#include <stdio.h>    //--------实现hannuota攻略程序
int hannuota(int n,char A,char B,char C)
{
	if(n==1){
		printf("Move %c to %c\n",A,C);
		return 0;
	}
	hannuota(n-1,A,C,B);
	printf("Move %c to %c\n",A,C);
	hannuota(n-1,B,A,C);

}
int main(void){
	int num=0;
	printf("输入塔的个数\n");
	scanf("%d",&num);
	hannuota(num,'A','B','C');
	return 0;
}

递归累加

递归函数来实现1+2+3+4+….+100

#include<stdio.h>//使用递归函数来实现1+2+3+4+....+100
int Plus(int num){
	if(num==1){
		return ;
	}
	Plus(num-1);
}
int main(void){
	printf("Please input a number to calculate\n");
	scnaf("%d",&num);
	Plus(num);
	return 0;
}

桶排序

#include <stdio.h>
char* Order(char* arr,int length)	//桶排序
{
	int max=0;
	int i=0;
	printf("%d",length);
	while(i<length)
	{
		if(*(arr+i)>max)
		{
			max=*(arr+i);
		}
		i++;
	}
	printf("%d\n",max);
}
int main()
{
	char arr[10]={1,34,32,34,11,3,35,67,89,22};
	Order(arr,sizeof(int));
	return 0;
}

宏定义

#include <stdio.h>
void Define_Undef()
{
	#define A "Hello"
	printf(A);
	#undef A
	#define A " World\n"
	printf(A);
}
void Define_Compare()
{
	#define CMP(a,b) (a>b?a:b)
	printf("MAX: %d",CMP(1,2));

}
void If_Endif_Elif()
{	
	#define TURE 1
	#define FALSE 0
	#define MAX(num1,num2) (num1>num2?TURE:FALSE)
	#define NUM 1
	#if NUM
	printf("Hello!\n");
	#endif
	#undef NUM
	#define NUM1 1
	#define NUM2 2
	#if MAX(NUM1,NUM2)
	printf("%d > %d \n",NUM1,NUM2);
	#elif !(MAX(NUM1,NUM2))
	printf("%d < %d\n",NUM1,NUM2);
	#endif
}
void Ifdef_Else_Endif()
{
//	#define IF
	#ifdef IF
	printf("IF has defined\n");
	#else
	printf("IF has not defined\n");
	#endif
}
void main()
{
	//Define_Undef();
	//Define_Compare();
	//If_Endif_Elif();
	Ifdef_Else_Endif();
}

位域

bitfiled

#include <stdio.h>
typedef struct bs {
	int a:2;
	int b:1;
	int c:12;	
	unsigned d:4

}bs;
struct bit_2 {
	unsigned a:2;
	unsigned :2;  //It can't use
	unsigned :0;  //NULL

	unsigned b:4;
	unsigned c:4;
	
};
int main(void) {
	bs bit;
	printf("sizeof(%d) \n",sizeof(struct bs));
	bit.a = 4;
	bit.b = 1;
	bit.c = 34235;
	printf("a: %d   b: %d  c: %d\n", bit.a, bit.b, bit.c);

	return 0;
}