programming

Question

Ouput

#include<Stdio.h>

int main()

{

int a=10;

a=a+ ~a;

printf(“%d”,a);

}

 

PS:i m getting 15 but 15 is nt ans.

Comments

-1 ?

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~ does bitwise complement.

You are getting 15 bcoz you are taking 10 as 1010 and then complementing it to get 5, but an int is representes by 2 bytes in turbo C compiler and 4 bytes in many other compilers i.e. 32 bits

Now try.

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01010=10
10101= -16+4+1 = -11
Addition gives -1

Didn't write other bits because of sign extension

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Yeah correct. Instead of writing all 32 bits, you can save time by writing only 5 bits, since rest bits are only sign extension and gives the same ans.

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yes -1 is ans.

@Kunal Kadian i did nt get it. how it effect the problem result??

@prashant jha 1  "Didn't write other bits because of sign extension" ?

 

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@Abhisek Tiwari 4

10 is ==> 00000000000000000/00000000001010

~10  ==> 11111111111111111111111111110101

~10 can be simplified to 10101 (chopping extended sign bits)

both represents same value i.e. -11

note:- Numbers are stored in 2's complement Representation.

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"Numbers are stored in 2's complement Representation." got it.

Thanks @Kunal Kadian @prashant jha 1 @Deepanshu

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why is 10 = 01010 not stored in 2s complement form ?😅

1010 = -8+2 = 6.

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It is in 2's complement form.

In 2's complement form, +ve no's are repreerepre as they are and -ve no's are represented as 2's complement of their positive counterpart.

Eg :-  -123 will be represented as 2's complement of 123.

86 will be represented as 86 only bcoz its +ve

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please correct me.

a= 10;( 00001010)

~a is 1s complement of a i.e. 11110101

we are interpreting ~a as 1s complement but we are taking  2s complement value of ~a when interpreting it as decimal

i.e. ~a= 10101= -16+4+1 = -11

why ?

because "Numbers are stored in 2's complement Representation."