1、不调用C++/C的字符串库函数，编写strcpy函数
char *strcpy(char *pDest, const char *psrc) {
assert((pDest != NULL)&&(psrc != NULL));
char *address = pDest;
while ( (*pDest++ = *psrc++) != '\0' )
{
}
return address;
}
上述strcpy能够把psrc的内容复制给pdest，为什么还要返回指针地址？
为了实现链式表达式：比如
int length=strlen(strcpy(strDest,“helloworld”));
2、编写类String的普通构造函数、拷贝构造函数、析构函数和赋值函数。
class String{
public:
String(const char* str = NULL) //普通构造函数
{
if ( NULL == str )
{
m_data = new char[1];
*m_data = '\0';
}
else {
int nLen = strlen(str);
if (m_data != NULL)
{
delete[]m_data;
m_data = NULL;
}
m_data = new char[nLen + 1];
strcpy(m_data, str);
}
}
String(const String &other) //拷贝构造函数
{
int nLen = strlen(other.m_data);
m_data = new char[nLen + 1];
strcpy(m_data, other.m_data);
}
~String() //析构函数
{
if ( NULL != m_data )
{
delete []m_data;
m_data = NULL;
}
}
String &operator=(const String &other) //赋值函数
{
if (this == &other )
{
return *this;
}
delete[]m_data;
int nLen = strlen(other.m_data);
m_data = new char[nLen + 1];
strcpy(m_data, other.m_data);
return *this;
}
private:
char *m_data;
};
3、在不使用第三方参数的情况下，交换两个参数i,j的值
void main()
{
int i = 1;
int j = 2;
i = i + j;
j = i - j;
i = i - j;
}
