strdup()函数实现

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

char * my_strdup(char *src);
char *my_strdup(char *src)
{
if(NULL == src)
{
return NULL;
}
char *p_src = NULL;
p_src = src ;
int count = 0 ;
while(*p_src != '\0')
{
count++;
p_src++;

}
char * new_addr  = (char *)malloc(sizeof(char)*(count+1));
p_src = src;
while(*p_src  != '\0')
{
*new_addr++ = *p_src++;

}
*new_addr = '\0';
return (new_addr -(count));

}
int main()
{

char src[] = "liusenlin";
printf("之前地址：\n");
printf("%p\n",src);
char *result  = NULL;
result = my_strdup(src);
printf("字符串拷贝后地址：\n");
printf(" %p\n",result);
printf("%s\n",result);
free（result）;
return 0;
}