How to make blank entry = default

This is a discussion on How to make blank entry = default within the C++ Programming forums, part of the General Programming Boards category; Hi! Just wondering, how to turn a normal "Enter" response to a default entry? i.e. Code: float number1; cin Input ...

  1. #1
    Registered User
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    Jul 2008
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    Question How to make blank entry = default

    Hi!

    Just wondering, how to turn a normal "Enter" response to a default entry?

    i.e.

    Code:
    float number1;
    cin Input number: ;
    if (number1 = (blank entry or "Enter"){
    number1 = 0.02;
    }
    Thanks.

  2. #2
    Cat without Hat CornedBee's Avatar
    Join Date
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    8,893
    Use std::getline to read a line of input instead of reading the integer directly. If the line is empty, use a default value, else parse the integer from the line.
    All the buzzt!
    CornedBee

    "There is not now, nor has there ever been, nor will there ever be, any programming language in which it is the least bit difficult to write bad code."
    - Flon's Law

  3. #3
    Registered User
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    Oct 2001
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    >Just wondering, how to turn a normal "Enter" response to a default entry?
    First read the input into a string first. At that point, there are several different ways to proceed. Here is one method:
    Code:
    	std::string snum;
    	double num;
    
    	std::cout << "Enter a number (or press <ENTER> for default):";
    	std::getline(cin, snum);
    
    	std::istringstream converter(snum);
    	converter >> num;
    
    	if (!converter)
    	{
    		if (converter.eof())
    		{
    			std::cout << "No value was entered.  A default value will used." << endl;
    			num = .02;
    		}
    	}
    	std::cout << num << std::endl;

  4. #4
    Registered User
    Join Date
    Jul 2008
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    26

    Alrighty

    Quote Originally Posted by swoopy View Post
    >Just wondering, how to turn a normal "Enter" response to a default entry?
    First read the input into a string first. At that point, there are several different ways to proceed. Here is one method:
    Code:
    	std::string snum;
    	double num;
    
    	std::cout << "Enter a number (or press <ENTER> for default):";
    	std::getline(cin, snum);
    
    	std::istringstream converter(snum);
    	converter >> num;
    
    	if (!converter)
    	{
    		if (converter.eof())
    		{
    			std::cout << "No value was entered.  A default value will used." << endl;
    			num = .02;
    		}
    	}
    	std::cout << num << std::endl;
    Sweet, thank you.

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