Question

一个简单的c语言程序。帮看下为什么VC6.0编译能通过，运行却出错。

#include<stdio.h>
void main()
{
void copy_string(char *from,char *to);
char *a="I am a teacher";
char *b="You are a student";
copy_string(a,b);
printf("a is %s\nb is %s\n",a,b);
}
void copy_string(char *from,char *to)
{
while(*from!='\0')
{
*to=*from;
from++;
to++;
}
*to='\0';
}

Answer 1

char *a="I am a teacher";
正确写法应为:const char *a="I am a teacher";
因为a指向一个常量字符串
所以不能在copy_string函数中修改a所指向的内存空间的内容。
char *b同理

修改：
#include<stdio.h>
void main()
{
void copy_string(char *from,char *to);
char a[]="I am a teacher"; //修改
char b[]="You are a student";//修改
copy_string(a,b);
printf("a is %s\nb is %s\n",a,b);
}
void copy_string(char *from,char *to)
{
while(*from!='\0')
{
*to=*from;
from++;
to++;
}
*to='\0';
}

Answer 2

我这运行成功

#include<stdio.h>

void copy_string(char *from,char *to);

int main()
{

char *a="I am a teacher";
char *b="You are a student";
copy_string(a,b);
printf("a is %s\nb is %s\n",a,b);
}
void copy_string(char *from,char *to)
{
while(*from!='\0')
{
*to=*from;
from++;
to++;
}
*to='\0';
}

Answer 3

#include <stdio.h>

char* copy_string(char *from,char *to);

void main()
{

char a[]="I am a teacher";
char b[]="You are a student";
copy_string(a,b);
printf("a is %s\nb is %s\n",a,b);
}
char* copy_string(char *from, char *to)
{
char* address= to;
while(*from != '\0')
{
*to = *from;
from++;
to++;
}
*to='\0';

return address;
}

楼主就是写个字符串拷贝函数然后调用

我改了下 楼主看看 可以正常拷贝