Thread: How can I get a fixed length string without side-effect?

  1. #1
    Registered User
    Join Date
    Nov 2009
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    5

    Question How can I get a fixed length string without side-effect?

    Hi there,

    Here is what I've tried:
    Code:
    #include<stdio.h>
    
    int main(){
      char str[10];
      int a;
      fgets(str, 10, stdin);
      scanf("%d", &a);
      printf("str is %s and the int is %d.\n", str, a);
    }
    the result is:
    $ ./test
    abc 123 37482 <-- input
    str is abc 123 3 and the int is 7482. <-- output
    The str is what I want but the int is not.
    What I want is like this:
    $ ./test
    abc 123 37482 <-- input
    123 <-- another input for the int
    str is abc 123 3 and the int is 123. <-- output
    How can I achieve this?

  2. #2
    Jack of many languages Dino's Avatar
    Join Date
    Nov 2007
    Location
    Katy, Texas
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    2,309
    Since fgets() is truncating the string because you have limited it, the remaining chars are still in the input buffer. Suck them out until you have sucked out the newline. Then, issue the scanf().
    Mac and Windows cross platform programmer. Ruby lover.

    Quote of the Day
    12/20: Mario F.:I never was, am not, and never will be, one to shut up in the face of something I think is fundamentally wrong.

    Amen brother!

  3. #3
    Registered User
    Join Date
    Nov 2009
    Posts
    5
    Oh, I see. Thank you!

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