高分问关于char*的问题，大侠请进

[IonEdge]

char *a = "bcd";
char *b = "faf";
a = b;
或者
memset(a,0,strlen(a)+1);
memcpy(a,b,strlen(a)+1);

是不是不管哪种方法，此时a的值还是"bcd";还是未定义的值？
如果改不了，那么是不是意味着char *a 只能在初始化的时候给他赋值一次

如果是这种情况呢：
char *a = new char[100];
char *b = "faf";
能不能给a多次赋值，还是只能赋初值，多谢了
解释下原因

[sankt]

char *a = "bcd"; //这样实质上是const char *a="bcd"; a指向的内存是只读的.

char *a = new char[100];
char *b = "faf";
这样可以给a多次赋值

[IonEdge]

那请问这段代码为什么会有问题：

#include <iostream>
#include <string>
using namespace std;

class CWord{
public:
CWord(char* s){
_word = new char[strlen(s)+1];
memset(_word,0,strlen(s)+1);
memcpy(_word,s,strlen(s)+1);
_size = strlen(s) + 1;
}
~CWord(){
delete[]_word;
}

void operator = (char *ch);
void inverse();
char* GetWord()const;
int GetSize()const;
private:
char* _word;
int _size;
};

ostream& operator << (ostream& os,CWord& word){
os << word.GetWord();
return os;
}

void CWord :: operator = (char *ch){
memset(_word,0,strlen(_word)+1);
memcpy(_word,ch,strlen(ch)+1);
}
void CWord::inverse(){
for(int i = 0;i <= (_size-1)/2-1; i++){
char temp = _word[i];
_word[i] = _word[_size - 2 - i];
_word[_size - 2 - i] = temp;
}
}

char* CWord :: GetWord()const{
return _word;
}

int CWord :: GetSize()const{
return _size;
}
void main()
{
CWord myword("i love you");
myword.inverse();
char seps[] = "' '";;
char s[100];
memset(s,0,100);
memcpy(s,myword.GetWord(),myword.GetSize());
char* token = strtok(s,seps);
CWord word(token);
while(token != NULL){
// CWord word(token);
word = token;
word.inverse();
cout << word;
token = strtok(NULL,seps);
}
}//本应该输出you love i的

[IonEdge]

以上问题找到了，新问题：
#include <iostream>
#include <string>
using namespace std;

class CWord{
public:
CWord(char* s){
_word = new char[strlen(s)+1];
memset(_word,0,strlen(s)+1);
memcpy(_word,s,strlen(s)+1);
_size = strlen(s) + 1;
}
~CWord(){
delete[]_word;
}

void operator = (char *ch);
void inverse();
char* GetWord()const;
int GetSize()const;
private:
char* _word;
int _size;
};

ostream& operator << (ostream& os,CWord& word){
os << word.GetWord();
return os;
}

void CWord :: operator = (char *ch){
memset(_word,0,strlen(_word)+1);
memcpy(_word,ch,strlen(ch)+1);
_size = strlen(ch)+1;
}
void CWord::inverse(){
for(int i = 0;i <= (_size-1)/2-1; i++){
char temp = _word[i];
_word[i] = _word[_size - 2 - i];
_word[_size - 2 - i] = temp;
}
}

char* CWord :: GetWord()const{
return _word;
}

int CWord :: GetSize()const{
return _size;
}
void main()
{
CWord myword("i love you");
myword.inverse();
char seps[] = "' '";;
char s[100];
memset(s,0,100);
memcpy(s,myword.GetWord(),myword.GetSize());
char* token = strtok(s,seps);
CWord word(token);
while(token != NULL){
// CWord word(token);
word = token;
word.inverse();
cout << word;
token = strtok(NULL,seps);
}
}
//结果正确，运行期有错误

[guyanhun]

浅拷贝的问题

[zephyr007]

operator = 重载有问题，_word缓冲区大小可能不足以容下ch的长度，应先判断ch的长度，必要情况向重新分配_word,然后再memcpy

[iicpp]

函数写得有问题。
void CWord :: operator = (char *ch){
delete [] _word;
_size = strlen(ch)+1;
_word = new char[_size];
memset(_word,0,_size);
memcpy(_word,ch,_size);
}

此外，要写得完整，还需要考虑写拷贝构造函数，运算符重载operate = (const CWord &)

[angel_rabbit]

studying