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最新推荐文章于 2024-11-16 19:52:04 发布

原创最新推荐文章于 2024-11-16 19:52:04 发布 · 1.4k 阅读

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#byte #include #string

博客给出了一段C语言代码，包含strcpy和memcpy函数的实现及使用示例。在main函数中定义字符串并调用这两个函数进行复制操作，最后输出结果。代码中还使用了assert进行断言检查。

#include <assert.h>
#include <stdio.h>

char * strcpy(char * str_to, const char * str_from);
void * memcpy(void * str_to, const void * str_from, size_t size);

int main(int argc, char* argv[])
{
char from[] = "this is the string will be copied! ";
enum {size = sizeof(from)};
char to[size] = {0};

assert(to != 0);
strcpy(to, from);
printf("use the strcpy : %s./n", to);

memcpy(to, from, sizeof(from));
printf("use the memcpy : %s./n", to);

return 0;
}

char * strcpy(char * str_to, const char * str_from)
{
assert(str_to != 0);
assert(str_from != 0);

char * p_to = str_to;
const char * p_from = str_from;

while( (*(p_to++) = *(p_from++)) != '/0' );

return p_to;
}

void * memcpy(void * str_to, const void * str_from, size_t size)
{
assert(str_to != 0);
assert(str_from != 0);

typedef unsigned char byte;
byte * p_to = (byte*)str_to;
const byte * p_from = (const byte *)str_from;

while( size-- > 0)
*(p_to++) = *(p_from++);

return p_to;
}