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How to check whether a string is number

Discussion in 'C' started by qiqinuinaifen128, Jan 15, 2008.

  1. qiqinuinaifen128

    qiqinuinaifen128 New Member

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    if i have a string, how do i check whether the string is number?
     
  2. technosavvy

    technosavvy New Member

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    look for atoi() function...
    it will return zero if it is not able to convert the string passed into number..

    though if you have an alphanumeric inputs (like 1234go4expert)..u should go for strtol()..

    both the functions even convert the input passed into their respective numbers(if possible).
     
  3. Salem

    Salem New Member

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    Please don't PM me for 1:1 support.
    You should use strtol() all the time.
    atoi() for example cannot detect numeric overflow.
     
  4. technosavvy

    technosavvy New Member

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    completely agree..
    there is another kind of case ..when input is "1234forum"
    atoi() will return 1234..!!

    and in case of strtol() using the third argument we can check if the function traversed the whole input or not..
     
  5. qiqinuinaifen128

    qiqinuinaifen128 New Member

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    Thank you so much. I will try it
     

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