#include <iostream>
using namespace std;
#include <string>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

//function
string * split(string a1, string t1);

int main(int argc, char** argv) {
	//1.C++ 字串 成員函式
	string a1 = "cpp is easy to learn, cpp is great.";
	string * a2 = new string("cpp is easy to learn, cpp is great.");

	//（1）目的：把cpp取代成javascript
	//方法：迴圈內，使用 find()，傳回位置，然後replace該位置，該舊文字長度，換成新文字，  
//	cout<<a1.find_first_of("cpp",0)<<endl;
	
	cout<<"a1 = "<<a1<<endl;
	while(true)
	{
//		int pos = a1.find_first_of("cpp",0);//從第0位置開始找
		int pos = a1.find("cpp",0);//從第0位置開始找
		if(pos == -1)break;
		string t1 = "cpp";//不能直接寫"cpp".size() 
		a1.replace(pos,t1.size(),"javascript");	
	} 
	cout<<"\na1 = "<<a1<<endl;
		
	//o（2）size_t find_first_of (const string& str, size_t pos = 0) const;
	//從 pos 開始，找出 str 中的任何一個字元，第一次出現的位置。若不存在，值為 npos(-1) 。
	//目的：尋找"abcde"裡面，第一個出現的位置 
	//注意，find_first_of()與find()不同，
	//find()：找字串的位置
	//find_first_of()：找任一字元的位置 
	a1 = "cpp is easy to learn, cpp is great.";
	size_t pos2 = a1.find_first_of("ab",0);
	cout<<"\n ab 第一個出現位置 = "<<pos2<<endl; 
	
	
	//o	（3）string substr (size_t pos = 0, size_t len = npos) const;
	//運算出一個新的 stirng 物件，其內容為本物件? pos 開始長度 len 的內容。
	//目的：取出『子字串』
	a1 = "cpp is easy to learn, cpp is great.";
	string t1 = a1.substr(0,3);
	cout<<"\n子字串 = "<<t1<<endl; 
	 
	//o	（4）切割字串成陣列
	a1 = "cpp, is easy to learn, cpp is great.";
	cout<<"\na1 = "<<a1<<endl;
	
	//目的：根據『,』，分割成子字串陣列
	t1 =",";
	//先計算『,』的數目
	int num = 0;
	int posbegin=0;
	while(true)
	{
		int posback = a1.find(t1, posbegin);//從位置0開始搜尋
		if(posback == -1)break;
		else num++;
		//修正posbegin的起始位置 
		posbegin = posback + t1.size();
	}
	cout<<"find ',' num = "<<num<<endl;
	
	//宣告子字串陣列（2個, 會有三個元素）=> num+1 
	string strary[num+1];
	//element 1
	int p1 = a1.find(",",0); 
	
	strary[0] = a1.substr(0, p1);
	cout<<"\n p1 = "<<p1<<", strary[0] = "<<strary[0]<<endl;
	
	//element 2
	int p2 = a1.find(",",p1+1); 
	strary[1] = a1.substr(p1+1, p2-(p1+1));
	cout<<"p2 = "<<p2<<", strary[1] = "<<strary[1]<<endl;
	
	//element 3
	int p3 = a1.find(",",p2+1); 
	strary[2] = a1.substr(p2+1, p3-(p2+1));
	cout<<"p3 = "<<p3<<", strary[2] = "<<strary[2]<<endl;
	
	//o	（5）切割字串成陣列：寫成 函數
	a1 = "cpp, is easy to learn, cpp is great.";
	cout<<"\na1 = "<<a1<<endl;
	t1 = ",";
//	string strary1[3];
	//字串陣列 = 字串指標，函數傳回值若是字串陣列（就傳回字串指標） 
	string * strary1 = new string[3]; 
	strary1 = split(a1, t1); 
	//output	
	cout<<"\nstrary1[0] = "<<strary1[0]<<endl;
	cout<<"\nstrary1[1] = "<<strary1[1]<<endl;
	cout<<"\nstrary1[2] = "<<strary1[2]<<endl;
	
	//o	（1）int compare (const string& str) const;
	//與 str 比大小。正值、零、負值分別代表大於、等於、小於。


	return 0;
}

//function 
string * split(string a1, string t1)
{
	//目的：根據『,』，分割成子字串陣列
	//先計算『,』的數目
	int num = 0;
	int posbegin=0;
	while(true)
	{
		int posback = a1.find(t1, posbegin);//從位置0開始搜尋
		if(posback == -1)break;
		else num++;
		//修正posbegin的起始位置 
		posbegin = posback + t1.size();
	}
	//cout<<"find ',' num = "<<num<<endl;
	
	//宣告子字串陣列（2個, 會有三個元素）=> num+1 
//	string strary[num+1];
	string * strary = new string[num+1];
	int p1=0;//搜尋t1起始位置 
	for(int i=0;i<=num;i++)
	{
		int p2 = a1.find(t1, p1); 
		strary[i] = a1.substr(p1, p2-p1);//p2-p2=中間的元素內容 
		p1 = p2 + 1;//p1是t1(,)的位置，下個元素要從p1+1開始 
	}
	
//	cout<<"\nstrary[0] = "<<strary[0]<<endl;
//	cout<<"\nstrary[1] = "<<strary[1]<<endl;
//	cout<<"\nstrary[2] = "<<strary[2]<<endl;
	
	//return
	return strary;
}