It is a rule in math that the absolute value of a number must be no less than zero. Is it true in computer languages? Well, most of the case except one. Let me take C language for example.

For a 32-bits C interger, its value ranges from [-2147483648, 2147483647] .So for x = -2147483648, what is the result of abs(x)? 2147483648, -2147483648, 2147483647, 0 or something else?

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