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

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.

Most computers these days use two's complement for signed integers, but it can vary by hardware architecture, programming language, or other platform-specific issues.

For a two's-complement representation, the most-significant ("leftmost") bit is referred to as the sign bit, and it will be set for a negative integer and clear for a non-negative integer. However, it is more than just a "flag". See the Wikipedia article for more information.