explain the output ?????

This is a discussion on explain the output ????? within the C Programming forums, part of the General Programming Boards category; Q) Find the output of: Code: void main() { int k=35; printf("%d %d %d",k==35,k=50,k>40); } OUTPUT IS: 0 50 0 ...

  1. #1
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    Question explain the output ?????

    Q) Find the output of:

    Code:
     
    void main()
            {
            int k=35;
            printf("%d %d %d",k==35,k=50,k>40);
            }
    OUTPUT IS:
    0 50 0

    but why not the output is 1 50 0 (as 35==35)

    second is:

    Code:
     
    void main()
            { 
            intx=15;
            printf("%d %d %d",x!=15,x=20,x<30);
            }
    OOUTPUT IS:
    1 20 1

    but according to me output should be 0 20 1 (asx!=15 i.e. 15!=15 is false i.e. 0) why is it not so.

  2. #2
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    The arguments to a function, in this case prinf, can be executed in any order. In this case the compiler is choosing to execute third argument, the assignment, first.

    For this reason, you're not allowed to write to and read the same memory location in the same line, except if the value read is used to compute the new value written. There are exceptions, but they don't apply here.
    It is too clear and so it is hard to see.
    A dunce once searched for fire with a lighted lantern.
    Had he known what fire was,
    He could have cooked his rice much sooner.

  3. #3
    and the hat of wrongness Salem's Avatar
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    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  4. #4
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    Explain the output???

    If you give only the first one it gives the correct result.

    Code:
    #include <stdio.h>
    void main()
    {
          int k=35;
          printf("%d",k==35);
    }
    This gives the result as you expect.

    Go through the following code,

    Code:
    #include <stdio.h>
    void main()
    {
          int k=35;
          printf("%d");
    }
    This will print '35'. So '%d' gets value previously stored.

  5. #5
    Registered User claudiu's Avatar
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    Also, as a side thing, the correct main definition is int main(void) or int main(int argc, char *argv[]) not void main(). Read the FAQ.
    1. Get rid of gets(). Never ever ever use it again. Replace it with fgets() and use that instead.
    2. Get rid of void main and replace it with int main(void) and return 0 at the end of the function.
    3. Get rid of conio.h and other antiquated DOS crap headers.
    4. Don't cast the return value of malloc, even if you always always always make sure that stdlib.h is included.

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