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Converting From Pointer/Address to String for Validation

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Join Date: Apr 2008

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Reputation: BBustos is an unknown quantity at this point

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BBustos

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Converting From Pointer/Address to String for Validation

Apr 13th, 2008

I would first like to start this post with a sincere Thank you to everyone who has posted and will post help for my problem. Without you guys, I would be banging my head on my desk.

Well, I got another problem. This time with a function that takes a pointer as an input. My teacher has informed me that I must take that pointer or address (I can't remember which it is) and convert it to a string. From then, I need to check the validity of it (between 0 and 100).

Here's the code:

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bool GetScore(int *number)
{
	bool valid = true;
	char buf[30];
	int length;
	int i = 0;
	
	I know something goes here, I just don't know what. I was thinking "itoa" or something like that.

	cin.getline(buf, 30);

	length = strlen(buf);

	for (i = 0; i < length; i++)
	{
		if ((buf[i] < '0') || (buf[i] > '9'))
		{
			valid = false;
		}
	}
	return valid;
}

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Join Date: Aug 2007

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vmanes

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Re: Converting From Pointer/Address to String for Validation

Apr 13th, 2008

Please clarify - what is the pointer pointing to, a string or an int? Is your function supposed to do input? Your description sounds like its role is to validate something which was input elsewhere.

If you are testing that a some string content represents a number, your loop is valid for testing that it contains digits, but is not testing for the overall value of 0-100. Once you are certain the string contains only digits, you can convert it to the numeric value, using functions such as atoi( ), and then test the resulting number.

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Join Date: Jun 2007

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dougy83

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Re: Converting From Pointer/Address to String for Validation

Apr 13th, 2008

•

I must take that pointer or address (I can't remember which it is) and convert it to a string

I think you're mixed up a bit (or maybe I am). I'm assuming GetScore returns true if the user enters a valid number. You've got this correct.

I'm also assuming that GetScore is supposed to set number with the score that is entered (only if it's valid though). This requires a conversion from string to integer (you can use atoi, or preferably a stringstream).

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 CPP Syntax (Toggle Plain Text) 
bool GetScore(int *number)
{
	bool valid = true;
	char buf[30];
	int length;
	int i = 0;
 
	cin.getline(buf, 30);
 
	length = strlen(buf);
 
	for (i = 0; i < length; i++)
	{
		if ((buf[i] < '0') || (buf[i] > '9'))
		{
			valid = false;
		}
	}
 
	if(valid){
      // convert string to integer and assign it to number
      *number = atoi(buf);
      }
 
	return valid;
}
bool GetScore(int *number)
{
	bool valid = true;
	char buf[30];
	int length;
	int i = 0;
	
	cin.getline(buf, 30);

	length = strlen(buf);

	for (i = 0; i < length; i++)
	{
		if ((buf[i] < '0') || (buf[i] > '9'))
		{
			valid = false;
		}
	}
	
	if(valid){
      // convert string to integer and assign it to number
      *number = atoi(buf);
      }
      
	return valid;
}

Last edited by dougy83; Apr 13th, 2008 at 2:50 am. Reason: sounded rude

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Join Date: Apr 2008

Posts: 7

Reputation: BBustos is an unknown quantity at this point

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BBustos

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Re: Converting From Pointer/Address to String for Validation

Apr 13th, 2008

I was able to get it. You were right with you're coding and Vnames was right, I forgot to add the part that verifys if its between 0 and 100. which would make it.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
bool GetScore(int *number)
{
	bool valid = true;
	char buf[30];
	int length;
	int i = 0;
 
	cin.getline(buf, 30);
 
	length = strlen(buf);
 
	for (i = 0; i < length; i++)
	{
		if ((buf[i] < '0') || (buf[i] > '9'))
		{
			valid = false;
		}
	}
	if (valid)
	{
		*number = atoi(buf);
	}
 
	if ((*number < 0) || (*number > 100))
	{
		valid = false;
	}
 
	return valid;
}
bool GetScore(int *number)
{
	bool valid = true;
	char buf[30];
	int length;
	int i = 0;

	cin.getline(buf, 30);

	length = strlen(buf);

	for (i = 0; i < length; i++)
	{
		if ((buf[i] < '0') || (buf[i] > '9'))
		{
			valid = false;
		}
	}
	if (valid)
	{
		*number = atoi(buf);
	}
	
	if ((*number < 0) || (*number > 100))
	{
		valid = false;
	}

	return valid;
}