Gate 2016 Set 1 Digital Logic 2's complement representation

Question

Is 1's/2's complement valid only for negative numbers? If 2's complement of a number is 1111111111110101, then the number should be 0000000000001011. Then the decimal representation should be +11. But the answer is -11.

Comments

https://gateoverflow.in/39649/gate-2016-1-07

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But in the GATE question, it has not been specified that whether the number is signed or unsigned. So how can it be assumed to be signed? Or does this mean that if 2's complement is being represented, the number has to be negative?

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No Number can be positive . actually 2's compliment number are also weighted so just assign weight to the number you will get the answer. you can also use the concept of sign bit extension to reduce size of string

1111111111110101 is equivalent to 10101

now assign weight i.e -16 + 4 +1 =-11

or beta jaldi concept clear kar le Time bahut kam baki hai

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in question  16 bit 2′s complement representation of an integer given and in  2′s complement representation the most significant bit is called the sign bit.