Question

用c++编写strcpy

Answer 1

/*
* An implementation of strcpy.
*/
char *strcpy1(char *target, const char *source)
{
int i;

for(i = 0; source[i] != '\0'; ++i)
target[i] = source[i];
target[i] = source[i];

return target;
}

#include <stdio.h>
int main()
{
char s1[] = "Hi there, fred!";
char s2[40];

strcpy(s2, s1);
printf("%s\n", s2);
}

Answer 2

char* strcpy(char* des,const char* source)
　
{
　
char* r=des;

assert((des != NULL) && (source != NULL));

　while((*des++ = *source++)!='\0');

　return r;
　
}

Answer 3

从安全角度看，这个还是不安全的，考虑到串的长度；建议用s_strcpy
char *strcpy1(char *target, const char *source)
{
if( !target || !source )
return NULL;
char *head = target;
while( *target-- = *source-- );
return head;
}

#include <stdio.h>
int main()
{
char s1[] = "Hi there, fred!";
char s2[40];

strcpy1(s2, s1);
printf("%s\n", s2);
}