Memory related question in C

This is a discussion on Memory related question in C within the C Programming forums, part of the General Programming Boards category; I want to write a c program to display list of data types and their corresponsing memory allocation size There ...

  1. #1
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    Memory related question in C

    I want to write a c program to display list of data types and their corresponsing memory allocation size

    There is any keyword in C which prints that "int" occupies "16" bits or such a kind of code is available ?

    Please give me some suggestions.

    Thanks
    TheDeveloper

  2. #2
    Registered User NeonBlack's Avatar
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    the sizeof operator prints the number of bytes.
    I copied it from the last program in which I passed a parameter, which would have been pre-1989 I guess. - esbo

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    thanks for the quick answer

    If there any way to find print minimum and maximum value accupied by different data types ?

    say for example

    "int" ranges between "-32,768 -> +32,767"

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    and the Hat of Guessing tabstop's Avatar
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    Macros for the integer types are in limits.h. Macros for the floating-point types are in float.h.

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    Quote Originally Posted by tabstop View Post
    Macros for the integer types are in limits.h. Macros for the floating-point types are in float.h.
    can you please explain me with sample code to retrieve that data from limits.h ?

    thanks in advance

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    Woof, woof! zacs7's Avatar
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    They're macros / constants -- see a list at http://www.cplusplus.com/reference/clibrary/climits/

    As for using them, checkout the tutorial on this website http://www.cprogramming.com/tutorial/cpreprocessor.html

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    Quote Originally Posted by TheDeveloper View Post
    can you please explain me with sample code to retrieve that data from limits.h ?
    As zacs7 noted, they are constants and by the time the program is executed, the pre-processor would have already replaced every instance of "INT_MAX" w/ 1240 (as an example).
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    Quote Originally Posted by zacs7 View Post
    They're macros / constants -- see a list at http://www.cplusplus.com/reference/clibrary/climits/

    As for using them, checkout the tutorial on this website http://www.cprogramming.com/tutorial/cpreprocessor.html
    Any luck that the values can be displayed using bitwise operator?

    thanks in advance

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    C++ Witch laserlight's Avatar
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    Quote Originally Posted by TheDeveloper
    Any luck that the values can be displayed using bitwise operator?
    No, since bitwise operators do not display anything. You can use bitwise operators with them, just as you can use bitwise operators with literals.
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    Quote Originally Posted by TheDeveloper View Post
    Any luck that the values can be displayed using bitwise operator?

    thanks in advance
    Perhaps something like
    Code:
    unsigned min, max;
    min = 0;
    max = ~min;

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    Quote Originally Posted by itCbitC View Post
    Perhaps something like
    Code:
    unsigned min, max;
    min = 0;
    max = ~min;
    can someone explain what exactly this code does?

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    C++ Witch laserlight's Avatar
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    Quote Originally Posted by TheDeveloper
    can someone explain what exactly this code does?
    For an unsigned integer, zero must be the minimum value, so it simply sets that as such. It then flips all the bits of zero to give the maximum unsigned value.
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    and the Hat of Guessing tabstop's Avatar
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    Quote Originally Posted by TheDeveloper View Post
    can someone explain what exactly this code does?
    Yes.

    (If you're asking about bitwise operators, you should at least be able to recognize them when you see them -- ~ is bitwise not, which means max is assigned the bitwise complement of min (it has a 1 where min has a 0 and vice versa.)

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    if u write max = ~min, max will be stored with the 1's complement of min....

    As min is 0 max (in binary) will be 11111........1 31 times...

    Hence max gives the max value an unsigned int can store...

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    Quote Originally Posted by laserlight View Post
    For an unsigned integer, zero must be the minimum value, so it simply sets that as such. It then flips all the bits of zero to give the maximum unsigned value.
    thanks for your answer

    Code:
    #include<stdio.h>
    #include<conio.h>
    void main()
    {
     unsigned max,min;
     min = 0;
     clrscr();
     max = ~min;
     printf("%u",max);
     getch();
    }
     
    Output : 65535
    How to find similar way for floating point values ?

    thanks in advance

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