what is the meaning of these warnings..

This is a discussion on what is the meaning of these warnings.. within the C Programming forums, part of the General Programming Boards category; ||=== ff, Debug ===| warning: char format, different type arg (arg 2)| //on scanf warning: implicit declaration of function `strlen'| ...

  1. #1
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    what is the meaning of these warnings..

    ||=== ff, Debug ===|

    warning: char format, different type arg (arg 2)| //on scanf
    warning: implicit declaration of function `strlen'|
    warning: char format, different type arg (arg 2)| //scanf
    ||=== Build finished: 0 errors,3 warnings ===|

  2. #2
    Deathray Engineer MacGyver's Avatar
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    Quote Originally Posted by transgalactic2 View Post
    warning: char format, different type arg (arg 2)| //on scanf
    The compiler is telling you that you lied to scanf by giving it one type and telling it to expect another.

    Quote Originally Posted by transgalactic2 View Post
    warning: implicit declaration of function `strlen'|
    Probably forgot to #include <string.h>. You used the function without properly declaring it, just like it said. Including the header file would include a declaration of the function.

    Quote Originally Posted by transgalactic2 View Post
    warning: char format, different type arg (arg 2)| //scanf
    See first warning.

  3. #3
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    Quote Originally Posted by transgalactic2 View Post
    ||=== ff, Debug ===|

    warning: char format, different type arg (arg 2)| //on scanf
    warning: implicit declaration of function `strlen'|
    warning: char format, different type arg (arg 2)| //scanf
    ||=== Build finished: 0 errors,3 warnings ===|
    It means you called scanf() wrong, and you failed to include <string.h>
    Code:
    //try
    //{
    	if (a) do { f( b); } while(1);
    	else   do { f(!b); } while(1);
    //}

  4. #4
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    scanf("%70s",&f);

    f is declARED as char f[71];

  5. #5
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    And your point?

    %s and friends are expecting a char *. When you pass an array to a function, it decays to a pointer to its first element. This means this would work just fine:

    Code:
    scanf("%70s", f);
    On the other hand, &f is a different type than f. &f is a pointer to an array of 70 chars. That is totally different.

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