C Programming - Expressions - Discussion

Discussion Forum : Expressions - Find Output of Program (Q.No. 2)
2.
Assuming, integer is 2 byte, What will be the output of the program?
#include<stdio.h>

int main()
{
    printf("%x\n", -2<<2);
    return 0;
}
ffff
0  
fff8
Error
Answer: Option
Explanation:
The integer value 2 is represented as 00000000 00000010 in binary system.

Negative numbers are represented in 2's complement method.

1's complement of 00000000 00000010 is 11111111 11111101 (Change all 0s to 1 and 1s to 0).

2's complement of 00000000 00000010 is 11111111 11111110 (Add 1 to 1's complement to obtain the 2's complement value).

Therefore, in binary we represent -2 as: 11111111 11111110.

After left shifting it by 2 bits we obtain: 11111111 11111000, and it is equal to "fff8" in hexadecimal system.
Discussion:
33 comments Page 4 of 4.

Veera said:   7 years ago
Why added 2? Explain here.

Tamilselvi said:   8 years ago
How it is equal to fff8?

Svetta said:   1 decade ago
How is shifting done?


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