收集C语言常用，经典代码。

[guixuhui2]

希望大家把好的代码分享出来。
我写写个：
将整型或浮点型转为字符串:

  int a=1234;
  float b=12.34;
  char a1[5];
  char b1[6];
  sprintf(a1,"%d",a);
  sprintf(b1,"%f",b);

[loonger110]

//int a[][];
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
a[i][j]=(i/j)*(j/i);

[guixuhui2]

[Quote=引用 13 楼 zm19870528 的回复:]
C/C++ code
unsngned int val = (a[0]<<24) ^ (a[1]<<16) ^ (a[2]<<8) ^a[3];
[/Quote]
你们能简明扼要的说明一下功能吗？

[如此美丽的你]

[Quote=引用 20 楼 zhao4zhong1 的回复:]
C/C++ code
#include <stdio.h>
int main() {
int IP[4];
int i;
char c;

printf("请输入一个ip地址:");
while (1) {
fflush(stdin);
if (5==scanf("%d.%d.%d.%d%c",&I……
[/Quote]
!!!!!!!!!!!!!!!!!!!!!!!!!!!good

[zdnexus]

MARK一下。。等下来抄一下。

[静革 justme0.com]

[Quote=引用 1 楼 hnuqinhuan 的回复:]
这儿还真的没写过
a = a ^ b;
b = a ^ b;
a = a ^ b;
[/Quote]

更简的：
a^=b;
b^=a;
a^=b;
记忆也方便。

我再写个： putchar(10);

[bruce_sha]

楼主等大家回答完，整理下发给大家

[safeqq4]

typedef struct __lock{
          unsigned char          status;
		  unsigned char          l_ber;
}__lock, __LOCK, *P__LOCK, **LP__LOCK;

#define                  BLOCK_NOT                0x00
#define                  BLOCK_OK                 0x01
#define                  BLOCK_EXIT               0x02

P__LOCK LockInit( void )
{
	P__LOCK l_hdr       = (P__LOCK)malloc(sizeof(struct __lock));
	if( l_hdr == NULL )
	{
		return NULL;
	}
	l_hdr->l_ber        = 0;
	l_hdr->status       = BLOCK_NOT;
	return l_hdr;
}

char Lock( P__LOCK m_lock )
{
	if( m_lock == NULL )
	{
		return -1;
	}
	++m_lock->l_ber;
	const unsigned char l_ber  = m_lock->l_ber;
	if( (m_lock->status & BLOCK_OK) == BLOCK_OK && m_lock->l_ber > 0 )
	{
        LockCf:NULL;
		while( (m_lock->status & BLOCK_OK) == BLOCK_OK )
		{
		    if( (m_lock->status & BLOCK_EXIT) == BLOCK_EXIT )
			{
			    return 0;
			}
		    Sleep(0);
		}
		if( m_lock->l_ber != l_ber )
		{
			goto LockCf;
		}
	}
	m_lock->status         |= BLOCK_OK;
	return 1;
}

char Unlock( P__LOCK m_lock )
{
	if( m_lock == NULL )
	{
		return -1;
	}
	--m_lock->l_ber;
	m_lock->status         &= (~BLOCK_OK);
	return 1;
}

[safeqq4]

随机取值算法范围（4字节）：

typedef struct __rantype
{
	        unsigned char        status;
	        unsigned long        ran_size;
			unsigned long        min_size;
			unsigned long        max_size;
}__rantype, __RANTYPE, *P__RANTYPE, **LP__RANTYPE;

DWORD WINAPI Trandom(PVOID f)
{
	P__RANTYPE m_ran                = (P__RANTYPE)f;
	if( m_ran == NULL )
	{
		return -1;
	}
	if( (m_ran->status & 0x01) != 0x01 )
	{
		return 0;
	}
	::SetThreadPriority(::GetCurrentThread(), THREAD_PRIORITY_IDLE);
	SYSTEMTIME m_time;
	unsigned long r_char            = 0;
	while( (m_ran->status & 0x02) != 0x02 )
	{		
	    ::GetLocalTime(&m_time);
		r_char                      = 0;
	    m_time.wSecond             += m_time.wMilliseconds;
	    if( (m_time.wMilliseconds & 0x0001) != 0x0001 )
		{
			++m_ran->ran_size;
	    	Sleep(m_time.wMilliseconds);
		}
		if( m_ran->ran_size > m_ran->max_size )
		{
			::GetLocalTime(&m_time);
			m_ran->ran_size        = m_time.wSecond;
		}
		if( m_ran->ran_size < m_ran->min_size )
		{
			m_ran->ran_size        = m_time.wSecond | (m_time.wMilliseconds << 16);
		}
		++m_ran->ran_size;
		Sleep(1);
	}
	m_ran->status                  = 0;
	return 1;	
}

void* RandomInit(unsigned long m_Min = 0, unsigned long m_Max = 0xffffffff)
{
	P__RANTYPE m_Random            = (P__RANTYPE)malloc(sizeof(__RANTYPE));
	if( m_Random == NULL )
	{
		return NULL;
	}
	m_Random->min_size             = m_Min;
	m_Random->max_size             = m_Max;
	m_Random->status               = 0x01;
	::CreateThread(NULL, NULL, Trandom, m_Random, NULL, NULL);
	return m_Random;
}

void FreeRandom(void* m_Ranp)
{
	if( m_Ranp == NULL )
	{
		return;
	}
	P__RANTYPE m_Random            = (P__RANTYPE)m_Ranp;
    m_Random->status               = 0x01 | 0x02;
	unsigned char m_Nber           = 0;
	while( m_Random->status != 0 && m_Nber < 254 )
	{
		++m_Nber;
		Sleep(100);
	}
	free(m_Random);
}

unsigned long GetRandoms(void* m_Ranp)              
{
	if( m_Ranp == NULL )
	{
		return 0;
	}
	P__RANTYPE m_Random            = (P__RANTYPE)m_Ranp;
	return m_Random->ran_size;
}

[朱韦刚]

hello world!!

[wang2666]

[Quote=引用 11 楼 zhao4zhong1 的回复:]

C/C++ code
#define SWAP(a,b) (a)^=(b)^=(a)^=(b)
[/Quote]
太给力了

[guixuhui2]

[Quote=引用 32 楼 safeqq4 的回复:]

C/C++ code

typedef struct __lock{
unsigned char status;
unsigned char l_ber;
}__lock, __LOCK, *P__LOCK, **LP__LOCK;

#define BLOCK_NOT ……
[/Quote]
这个是什么功能？

[鸟辉]

mark。。。。。。。。。。。。

[我的职业是看店铺的]

[Quote=引用 4 楼 yico_gaga 的回复:]
引用 2 楼 last_c_ 的回复:

printf("Hello world!\n");

这个入门必须写的~知道出处吗？
[/Quote]
相传那个啥通过无数的艰辛，建立C语言的时候，第一次在机器上输出的就是这么句hello word!
后来那个啥又进行了修改，人们的修改，最后成了那个经典的
main()
{
printf("Hello world");
}
后来就成为许多语言开头的第一句

[我的职业是看店铺的]

[Quote=引用 36 楼 guixuhui2 的回复:]
引用 32 楼 safeqq4 的回复:

C/C++ code

typedef struct __lock{
unsigned char status;
unsigned char l_ber;
}__lock, __LOCK, *P__LOCK, **LP__LOCK;

#define BLOCK_NOT ……

这个是什么功能？
[/Quote]
定义一个结构体

[fankys]

mark

[CrackValue]

想给力，但是我写的垃圾代码不敢拿出来见人啦，
呵呵，支持楼主，学习了

[guixuhui2]

大家给点力啊！有好的就分享出来嘛

[sunrier]

TC 2.0

[kingpin58]

MARK

[xiaolomg]

[Quote=引用 2 楼 last_c_ 的回复:]

printf("Hello world!\n");
[/Quote]
这样行啊