#include <stdio.h>
#include <assert.h>
#include <string.h>
//库函数strcpy时
//参数:dest为目标字符串,source(src)为原字符串。
char *my_strcpy(char *dest, const char *src)
{
assert(dest != NULL && src != NULL);
char *p = dest;
while((*p++ = *src++) != '\0'){}
return dest;
}
//库函数strncpy时
//参数:dest为目标字符串,source(src)为原字符串。(int)
/*char *my_strncpy(char *dest, const char *src, size_t n)
{
assert(dest != NULL && src != NULL);
while(n--)
{
dest[n] = src[n];
}
return dest;
}
char *my_strncpy(char *dest, const char *src, size_t n)
{
assert(dest && src);
int i = 0;
for(i = 0; i < n; i++)
{
dest[i] = src[i];
}
return dest;
}*/
int main ()
{
char str1[] = {"abcdefg"};//如果str1的内存小,str2内存多,是存不下的。
char str2[] = {"mmm"}; //内存是先存str1,再存的str2
printf("= %s\n", my_strcpy(str1, str2)); //结果mmm
// printf("= %s\n", my_strncpy(str1, str2, 1)); //结果mbcdfg (str2的前1位给str1)
return 0;
}