我们知道strcpy是字符串复制函数。
定义于：
[cpp]
string.h
声明：
[cpp]
char *strcpy(char *dest, const char *src);
原型：
[cpp]
#ifdef _NC_RESTRICT
char *strcpy(char *restrict dest, const char *restrict src)
#else
char *strcpy(char *dest, const char* src)
#endif
{
char *ret = dest;
while (*dest++ = *src++)
;
return ret;
}
1. 使用strlen实现
[cpp]
/*
* exercise01.c
*
* Created on: 2012-11-5
* Author: xiaobin
*
* Huawei face questions
*/
#include
#include
char *strcpy1(char *dest, const char *src)
{
char *ret = dest;
int len = strlen(src);
int i = 0;
while (len-- != 0) {
i++;
}
return ret;
}
int main(int argc, char* argv[])
{
char *s = "hello,world";
char *d;
strcpy1(d, s);
printf("%s\n", d);
return 0;
}
计算源串的长度，然后循环赋值。
2. 无strlen实现
[cpp]
/*
* exercise01.c
*
* Created on: 2012-11-5
* Author: xiaobin
*
* Huawei face questions
*/
#include
#include
char *strcpy1(char *dest, const char *src)
{
char *ret = dest;
int i = 0;
while (*src != 0) {
ret[i] = *src;
i++;
*src++;
}
return ret;
}
int main(int argc, char* argv[])
{
char *s = "hello,world";
char *d;
strcpy1(d, s);
printf("%s\n", d);
return 0;
}