Issue with cout for a char array. Appearance of weird character

[Viraldude]

I used the following code to reverse a char array (string). String itself is reversed but at the end of the string there appears an unusual character. This character repeats as many times as the length of array.

void reverseChar(char String[])
{
	//input is mystr
	//char mystr[] = "HelloWorld"
	const int x = countChar(String);
	//cout << "Entered reverseChar: " << x << endl;
	char newstring[10];
	for (int y = 0; y < x; y++)
	{
		//cout << "Itteration number: " << y + 1 << endl;
		newstring[y] = String[x - y-1];
		//cout << newstring[y] << endl;
	}
	cout << "Reversed string: " << newstring << endl;
}

[TwilightSpectre]

Works fine for me, if I replace countChar() with strlen(). Could we see your countChar() function? It is probably giving you a number too large.

[ne555]

you probably didn't zero terminated `newstring'

[Viraldude]

My countChar(char string[]) is:

int countChar(char String[])
{
	int length = 0;
	while (String[length] != '\0')
	{
		length++;
	}
	return length;
}

[Hiten Sharma]

Hey Viraldude your problem is very simple.........

you havn't used string terminator so the the emty indexes will show garbage values.................


just add this......

void reverseChar(char String[])
{
	//input is mystr
	//char mystr[] = "HelloWorld"
	const int x = countChar(String);
	//cout << "Entered reverseChar: " << x << endl;
	char newstring[10];
	for (int y = 0; y < x; y++)
	{
		//cout << "Itteration number: " << y + 1 << endl;
		newstring[y] = String[x - y-1];
		//cout << newstring[y] << endl;
	}
        newstring[y]='\0';
	cout << "Reversed string: " << newstring << endl;
}

[Viraldude]

That worked. Thank you very much!

[TwilightSpectre]

Um...
In your example, you are having a buffer overflow, which will occasionally cause errors. This is because you are declaring newstring as a string of size 10. If you passed, for example, "HelloWorld" (i.e. 10 characters), and added a null terminator, you would now have an array of size 10 holding data of size 11.

You probably want to dynamically allocate newstring to be 1 + the size of the string, like so:

int x =countChar(String);
char *newstring = new char[x + 1];
// ...
newstring[y] = '\0';
cout << "Reversed string: " << newstring << endl;
delete newstring;