the length of a string code

This is a discussion on the length of a string code within the C++ Programming forums, part of the General Programming Boards category; hi everyone, I am very new in C++ so I don't have much of knowledge about the language. The question ...

  1. #1
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    the length of a string code

    hi everyone,
    I am very new in C++ so I don't have much of knowledge about the language. The question is I have promoted my new program to enter 12 characters. So, now I want to check if the user have entered 12 characters exactly not less and not more. The code will include some numbers with some letters EX ( 345D3CC123FA ). How I can do that ? I know that I am going to use If statement but in the condition EX ( if ( my condition) ) I don't know how to tell the check if the user entered 12 characters or not... I hope it is clear..

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    What data type are you reading your string into? Does it have a built-in length function?

  3. #3
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    I don't know excatly what do you mean but this is all what I have gotten so far!

    Code:
    #include<string>
    using namespace std;
    
    	String i;
    	int n;
    	char codeRange[11];
    
    	
    
    int main()
    {
      	cout<< "please enter a serial number of 12 characters:";
    	cin >> i;
    	
    	if (i.length)
    	{
       // code to execute if condition is true
    	}
    	else 
    	{
       // code to execute if condition is false
    	}

  4. #4
    C++ Witch laserlight's Avatar
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    Since you included the <string> header, it looks like you want to use std::string, which does have a length() member function. However, C++ identifier names are case sensitive, so it should be string, not String.

    Oh, and it would be good to avoid global variables.
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  5. #5
    and the Hat of Guessing tabstop's Avatar
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    Well, what do you want to be true about i.length? That's what needs to go in the if () part.

  6. #6
    Jack of many languages Dino's Avatar
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    Try this:
    Code:
    	if (i.length()==12)
    Todd

  7. #7
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    I have completed my program but it has this Error E2379 CokeRewardCodes.cpp 18: Statement missing ; in function main()
    where is the error in this code ?

    Code:
     
    #include <iostream>
    #include<string>
    using namespace std;
    
    int main()
    {
       string i; 
    	int length=0;	
    	cout<< "please enter a serial number of 12 characters:";
    	cin >> i;
    	length=i.length();
    	
    	if (length!=12 )
    		cout << "The code you have entered cannot be processed because the code must be contained of 12 characters exactly";
    	else (length == 12)
    		cout << " that's correct code";
    
    	return 0;
    }

  8. #8
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    You meant "else if (length == 12)", but you could just write "else" since you already know in that case that length == 12.

  9. #9
    and the Hat of Guessing tabstop's Avatar
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    This is starting to become an epidemic.
    Code:
    else (length == 12)
    I didn't get line 18 when I counted, but who knows. Anyway, there's no reason to put a condition on an else statement, because an else statement doesn't need a condition. It's everything else, that is, everything that didn't make the first if true. So remove the condition length==12.

  10. #10
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    yeah that's right .. thanks so much the program is working!

  11. #11
    C++ Witch laserlight's Avatar
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    The problem is with:
    Code:
    else (length == 12)
    It should really just be else.

    Also, I would rename the string i to serial_number, and will not bother with a length variable unless it really is necessary to avoid calling length() multiple times.

    You could also be more consistent with your code indentation.
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