#define _CRT_SECURE_NO_WARNINGS
#include <cstdlib>
#include <iostream>
using namespace std;
////int strlen(const char * s)
////{
//// int i = 0;
//// for (; s[i]; ++i);
//// return i;
////}
////void strcpy(char * d, const char * s)
////{
//// int i = 0;
//// for (i = 0; s[i]; ++i)
//// d[i] = s[i];
//// d[i] = 0;
////
////}
int strcmp(const char * s1, const char * s2)
{
for (int i = 0; s1[i] && s2[i]; ++i) {
if (s1[i] < s2[i])
return -1;
else if (s1[i] > s2[i])
return 1;
}
return 0;
}
////void strcat(char * d, const char * s)
////{
//// int len = strlen(d);
//// strcpy(d + len, s);
////}
class MyString
{
private:
char* ptr;
int size;
public:
MyString(char* s = NULL){
if (s){
size = strlen(s);
ptr = new char[strlen(s) + 1];
strcpy(ptr, s);
}
else{
size = 0;
ptr = new char[1];
ptr[0] = 0;
}
}
~MyString(){
delete[] ptr;
}
void duplicated(const MyString& s){
if (size < s.size){
delete[]ptr;
ptr = new char[s.size + 1];
}
strcpy(ptr, s.ptr);
size = s.size;
}
MyString(const MyString& s) :size(0), ptr(new char[1]){
duplicated(s);
}
MyString& operator=(const char* s){
int len = strlen(s);
if (size < len){
delete[] ptr;
ptr = new char[len+ 1];
}
strcpy(ptr, s);
size =len;
return *this;
}
MyString& operator=(const MyString& s){
if (ptr == s.ptr)
return *this;
duplicated(s);
return *this;
}
char& operator[](int i){
return ptr[i];
}
MyString & operator+=(const char *s){
int len = strlen(s);
char* tmp = new char[size+len+ 1];
strcpy(tmp, ptr);
strcat(tmp, s);
delete[]ptr;
ptr = tmp;
size += len;
return *this;
}
MyString operator()(int i, int j){
char* tmp = new char[j + 1];
for (int t = i; t < i + j; ++t)
tmp[t - i] = ptr[t];
tmp[j] = '\0';
MyString s = tmp;
delete[]tmp;
return s;
}
friend MyString operator+(MyString &a, MyString &b);
friend ostream & operator<<(ostream &os, MyString & s);
friend MyString operator+(const char * str, MyString s);
friend MyString operator+(MyString s, const char *str);
friend bool operator<(MyString &s1, MyString &s2);
friend bool operator>(MyString &s1, MyString &s2);
friend bool operator==(MyString &s1, MyString &s2);
};
bool operator==(MyString &s1, MyString &s2){
return strcmp(s1.ptr, s2.ptr) == 0;
}
bool operator>(MyString &s1, MyString &s2){
return strcmp(s1.ptr, s2.ptr) > 0;
}
bool operator<(MyString &s1, MyString &s2){
return strcmp(s1.ptr, s2.ptr) < 0;
}
MyString operator+(MyString s, const char *str){
char* tmp = new char[strlen(s.ptr) + strlen(str) + 1];
strcpy(tmp, s.ptr);
strcat(tmp, str);
MyString s1=tmp;
delete[]tmp;
return s1;
}
MyString operator+(const char * str, MyString s){
char* tmp;
tmp = new char[strlen(str) + strlen(s.ptr) + 1];
strcpy(tmp, str);
strcat(tmp, s.ptr);
MyString s1= tmp;
delete[]tmp;
return s1;
}
MyString operator+(MyString &a, MyString &b){
char* tmp = new char[strlen(a.ptr) + strlen(b.ptr)+1];
strcpy(tmp, a.ptr);
strcat(tmp, b.ptr);
MyString s1 = tmp;
delete[]tmp;
return s1;
}
ostream & operator<<(ostream &os, MyString & s){
os << s.ptr;
return os;
}
int CompareString(const void * e1, const void * e2)
{
MyString * s1 = (MyString *)e1;
MyString * s2 = (MyString *)e2;
if (*s1 < *s2)
return -1;
else if (*s1 == *s2)
return 0;
else if (*s1 > *s2)
return 1;
}
int main()
{
MyString s1("abcd-"), s2, s3("efgh-"), s4(s1);
MyString SArray[4] = { "big", "me", "about", "take" };
cout << "1. " << s1 << s2 << s3 << s4 << endl;
s4 = s3;
s3 = s1 + s3;
cout << "2. " << s1 << endl;
cout << "3. " << s2 << endl;
cout << "4. " << s3 << endl;
cout << "5. " << s4 << endl;
cout << "6. " << s1[2] << endl;
s2 = s1;
s1 = "ijkl-";
s1[2] = 'A';
cout << "7. " << s2 << endl;
cout << "8. " << s1 << endl;
s1 += "mnop";
cout << "9. " << s1 << endl;
s4 = "qrst-" + s2;
cout << "10. " << s4 << endl;
s1 = s2 + s4 + " uvw " + "xyz";
cout << "11. " << s1 << endl;
qsort(SArray, 4, sizeof(MyString), CompareString);
for (int i = 0; i < 4; i++)
cout << SArray[i] << endl;
//s1的从下标0开始长度为4的子串
cout << s1(0, 4) << endl;
//s1的从下标5开始长度为10的子串
cout << s1(5, 10) << endl;
return 0;
}
全面的MyString
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转载自blog.csdn.net/weixin_45644911/article/details/104254737
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