Extending the string class

[DrakeMagi]

What would i have to do to expand on append operator+= . where i can add int,long, and etc. so i don't overwrite string append method.

This is what i have

#include <vector>
#include <string>
#include <sstream>

#ifndef ESTRING_HPP
#define ESTRING_HPP

class str;
typedef std::vector<str> svector;
typedef unsigned int uint;

class str : public std::string {
	
public:
	// string constructor
	str() : std::string() { }
	str( const std::string& s ) : std::string( s ) { }
	str( const std::string& s, std::size_t n ) : std::string( s,n ) { }
	str( const char *s, std::size_t n ) : std::string( s,n ) { }
	str( const char *s ) : std::string( s ) { }
	str( std::size_t n, char c ) : std::string ( n,c ) { }
	template <class InputIterator>
	str( InputIterator first, InputIterator last ) : std::string( first,last ) { }

	// extended methods
	svector split(str split=" ", uint limit=0);
	void join(str sept, svector &list); // make new string 
	void ajoin(str sept, svector &list);
	uint count(const str s) const;
	
	str lower();
	str upper();
	
	bool islower() const;
	bool isupper() const;
	bool isint() const;
	bool isfloat() const;
	bool isalpha() const;
	
	// convert str into a number
	template <typename T>
	T convert() { 
		T result = 0;
		if(isint() or isfloat()) {
			std::stringstream stream;
			stream << *this;
			stream >> result;
		}
		return result;
	}
};

#endif 

#include <iostream>

#include "estring.hpp"

using namespace std;

// take a line and split it into a vector
svector str::split(str split, uint limit) {
	svector list;
	size_t end,pos = 0;
	
	while(true) {
		end = find(split,pos);
		list.push_back(substr(pos,end-pos));
		pos = end + split.size();
		if(end == string::npos) break;
		if(limit != 0) {
			if(list.size() >= limit) {
				list.push_back(substr(pos));
				break;
			}
		}	
	}
	
	return list;
}

// combine a svector and replace string
void str::join(str sept, svector &list) {
	assign(list[0]);
	for(uint i = 1; i < list.size(); i++) {
		append(sept);
		append(list[i]);
	}
}

// append a svector to the string
void str::ajoin(str sept, svector &list) {
	for(uint i = 0; i < list.size(); i++) {
		append(sept);
		append(list[i]);
	}
}

// counts how many times it appears
uint str::count(const str s) const {
	uint total = 0;
	size_t end,pos = 0;
	
	while(true) {
		end = find(s,pos);
		if(end == string::npos)
			break;
		pos = end + s.size();
		total++;
	}
	return total;
}

bool str::islower() const {
	bool Bool = true;
	if (length() == 0)
		Bool = false;
	else {
		for(const_iterator i = begin(); i != end(); i++) {
			if(*i >= 'A' && *i <= 'Z') {
				Bool = false;
				break;
			}
		}
	}
	return Bool;
}

bool str::isupper() const {
	bool Bool = true;
	if (length() == 0)
		Bool = false;
	else {
		for(const_iterator i = begin(); i != end(); i++) {
			if(*i >= 'a' && *i <= 'z') {
				Bool = false;
				break;
			}
		}
	}
	return Bool;
}

bool str::isint() const {
	bool Bool = true;
	if (length() == 0)
		Bool = false;
	else {
		for(const_iterator i = begin(); i != end(); i++) {
			if(*i < '0' || *i > '9') {
				Bool = false;
				break;
			}
		}
	}
	return Bool;
}

bool str::isfloat() const {
	bool Bool = true;
	if (length() == 0)
		Bool = false;
	else if( count(".") != 1 )
		Bool = false;
	else {
		for(const_iterator i = begin(); i != end(); i++) {
			if((*i < '0' || *i > '9') && *i != '.') {
				Bool = false;
				break;
			}
		}
	}
	return Bool;
}

bool str::isalpha() const {
	bool Bool = true;
	if (length() == 0)
		Bool = false;
	else {
		for(const_iterator i = begin(); i != end(); i++) {
			if((*i < 'a' || *i > 'z') && (*i < 'A' || *i > 'Z') && *i != ' ') {
				Bool = false;
				break;
			}
		}
	}
	return Bool;
}

str str::lower() {
	for(iterator i = begin(); i != end(); i++) {
		if(*i >= 'A' && *i <= 'Z') 
			*i += ('a' - 'A');
	}
	return *this;
}

str str::upper() {
	for(iterator i = begin(); i != end(); i++) {
		if(*i >= 'a' && *i <= 'z') 
			*i -= ('a' - 'A');
	}
	return *this;
}
	
int main() {
	str combine("81.1");
	str test("split this line");
	svector slist;
	float nfloat;
	int nint;
	
	// convert into number
	nfloat = combine.convert<float>(); 
	cout << nfloat << endl;
	// convert into number
	nint = combine.convert<int>();
	cout << nint << endl;
	
	// count how many times it appears in string
	cout << test.count("li") << endl; 
	cout << test.count("e") << endl;
	cout << test.count("I") << endl;
	
	// seeing if its all char
	if(test.isalpha())
		cout << "True" << endl;
	else
		cout << "False" << endl;
	
		
	cout << test << endl;
	// split on a str
	slist = test.split(" ",1);
	for(uint i = 0; i < slist.size(); i++)
		cout << slist[i] << endl;
	
	// join it back to a string
	combine.join(" ", slist);
	cout << combine << endl;
	// appending , and join to end of string
	combine.ajoin(",",slist);
	cout << combine << endl;
	
	// change all letters to uppercase
	cout << test.upper() << endl;
	// change all letters to lowercase
	cout << test.lower() << endl;
	
	return 0;
}

[hamsterman]

I don't understand. Do you want to add str& operator += (int number); to your str class ? What is stopping you ?

[aquaz]

NEVER DERIVE FROM STD::STRING!!!
Generally, it is a very bad idea to derive from standard class, except thoses designed to derive from(exemple std::exception).
Why? because you don't know if the destructor is virtual(it is generally not) and therefore expose your program to memory leaks.
Here, you should use std::ostringstream if you want to add int, floats... to string, this is the standard way of doing:
http://www.cplusplus.com/reference/iostream/ostringstream/