Thread: String woes

Hi, I am working on a program that deals with strings. Basically, I want to check the integer value of each string and if the char's value is null, I want to make it one. Checking the value of the string is not hard, it is the part that deals with changing it's value. Here is my code:

Code:

for (int i=0; i < 6; i++)
	{
		if ((int)string[i] == 0)
		{
			(int)string[i] = 1;
		}
	}

I have a feeling it is something I don't know/understand with strings but any help will be appreciated. Thanks

yea
if str[0] == 0
str[0] = 1
something like that, sorry for all the pseudocode.

I've had code similar to that all night and all that happens when I run it is that Windows crashes. I just copied yours to make sure, Windows crashed as well. I have no idea why, that's why I posted here, I thought it was an insane string error but it compiles. I've had variations of that code for hours trying to figure this out. Blah, I probably need to restart and all my troubles will be solved.

Ok, I feel bad because I am trying to get better at contest programs and this was crashing windows but here goes, certain members might recognize it.

Code:

#include <iostream>
#include <string>
using namespace std;
int main()
{
	string comet;
	string group;
	int cometproduct = 1;
	int groupproduct = 1;

	cin >> comet;
	cin >> group;
	for (int i=0; i < 6; i++)
	{
		if ((int)comet[i] == 0)
		{
			comet[i] = 'A';
		}
	}
	cout << comet;

	return 0;
}

thank you, I need to read up more before I attempt harder problems on this string of contests, I generally know a lot about core language C++ coding but I lack a lot of little things such as that. thanks for the help!

All the char (letters, digits, punctuation marks) and many we don't routinely use are identified numerically in a character set. Thus, using the ASCII character set the char a has a numerical value of 97 and the char A has a value of 65, etc. The ASCII char set uses numerical values 0-127, the extended ASCII char set uses numerical values 0-255, and the unicode char set is identical to the extended ASCII character set for numerical values 0-255 but goes beyond there as well. The point is, the numerical value for the null character is zero. therefore, this:

char array[4];
array[0] = 0;

assigns the numerical value of zero, that is the null character, to the first element of array, and

array[1] = 65;

assigns the numerical value of 65, that is 'A', to the second element of array. At this point, array is both a valid char array and a valid string. However, as a string, it is an empty string, as the index for 'A' is after the index for the null char. In fact, strings can only have a single null char, and it is the last char of the string, even if there are other char after the null char in the char array. You can also have more than one null char in a char array, of course:

array[0] = 'A';
array[1] = 0;
array[2] = 'a';
array[3] = '\0';//just another way to express the null char.

now if you did this:

cout << array;

the output would be: A

However, if you did this:

Code:

for(int i = 0; i < 4; ++i)
{
    if(array[i] == 0)
       cout << '*';
    else
       cout << array[i];
}

the output would be:
A*a*

Thanks for the extra help, but I finished it last night, I still appreciate it though!