How are negative numbers represented in 32-bit signed integer?

Question

How are negative number represented in 32-bit signed integer? Is it two\'s or one\'s complement? or the last bit on the left is like a flag? For example: (-10)

Answer 1

I think the answer is 0110, preceeded by 1 repeated 28 times, therefore it looks like:

1111 1111 1111 1111 1111 1111 1111 0110;

Steps:

1. bit representation for 10 is:

   0000 0000 0000 0000 0000 0000 0000 1010;

2. 0->1 and 1->0 for all the bits:

   1111 1111 1111 1111 1111 1111 1111 0101;

3. add 1 to the last bit, and propagate to the bit ahead, done!

   1111 1111 1111 1111 1111 1111 1111 0110;

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You can verify by adding it with 10, and you will get 0 for all bits. As mentioned above, it is 2-based and follows two's complement.