Help needed in recursion.

This is a discussion on Help needed in recursion. within the C Programming forums, part of the General Programming Boards category; Code: #include<stdio.h> void print(char *p) { if(*p) print(++p); printf("%s\n",p); } main() { char *p="ABCD"; print(p); } for the above program ...

  1. #1
    Registered User
    Join Date
    Nov 2011
    Posts
    32

    Help needed in recursion.

    Code:
    #include<stdio.h>
    void print(char *p)
    {
    if(*p)
    print(++p);
    printf("%s\n",p);
    }
    main()
    {
    char *p="ABCD";
    print(p);
    }

    for the above program I'm expecting output as
    Code:
    (null)
    D
    CD
    BCD
    but the ACTUAL output is
    Code:
    (null)
    (null)
    D
    CD
    BCD
    Why printf is printing two NULL?

  2. #2
    C++ Witch laserlight's Avatar
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    Singapore
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    23,820
    Recall the effects of ++p.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  3. #3
    Registered User
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    Jan 2012
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    It increments to a null and in next call it's a null ( no increment ). Hence, prints both.

  4. #4
    - - - - - - - - oogabooga's Avatar
    Join Date
    Jan 2008
    Posts
    2,808
    You need to indclude the printf in your if block:
    Code:
    if(*p) {
    
      print(++p);
    
      printf("%s\n",p);
    }

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