Simple C++ question

Posted on 2013-01-28
Last Modified: 2013-01-28
Hello experts,

please have a look at the code below:

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

//tworze klase, ktora umozliwi dodawanie stringow oraz
//zapis stringow w postaci zmienna = "jakis string";

class String{
	char * string;

	String(const char* aChar){
		string = new char[????];   how can I determine the length of aChar here?
		strcpy(string, aChar);

		delete string;
		string = 0;

	char * getString(){
		return string;

	void operator = (char * aString){
		strcpy(string, aString);

	friend ostream& operator<< (ostream & aOstream, const String & aString);


ostream& operator<< (ostream & aOstream, const String & aString){
	aOstream << aString.string;
	return aOstream;

int main(){
	String string1("kdjshfgkljs");
	String string2("skldjhfls");

	cout << string1 << string2;

	return 0;

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Thank you

Question by:panJames
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LVL 31

Accepted Solution

Zoppo earned 500 total points
ID: 38827233
Hi panJames,

you can use strlen, i.e.:
string = new char[strlen(aChar)+1]; // need to add 1 for terminating NUL character

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Hope that helps,

LVL 31

Expert Comment

ID: 38830005
BTW, two more points:

1. In the constructor you should check if the passed string is a valid pointer.
2. The assignment operator isn't correctly implemented, it doesn't (re-)allocate the memory needed.

So I would change these two functions to look like this:
	String(const char* aChar){
		if ( aChar != 0)
			string = new char[strlen(aChar)];
			strcpy(string, aChar);
			string = 0;
			cout << "empty string"<< endl;

	void operator = (char * aString)
		delete [] string;
		string = 0;

		if ( aString != 0)
			string = new char[strlen(aString);
			strcpy(string, aString);

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