terse code for comparing 4 numbers

I've to compare 4 variables a,b,c,d if any of them is -1 return false. and How mush terse this could be ? may be some mathematical operation could be done !! I dont like wasting so many characters or 开发者_如何学JAVAlines for this simple thing.

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Normally:

return a!=-1 && b!=-1 && c!=-1 && d!=-1;

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Since ~(-1) == 0 in 2's complement machine, and 0 is a false value, we could reduce the above to

return ~a && ~b && ~c && ~d;

or, not relying on 2's complement:

return a+1 && b+1 && c+1 && d+1;

but it has undefined behavior on overflow.

(But please use the normal way. You may forget what this clever hack is doing years later.)

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If your numbers can be either non-negative or -1, then you can use the following:

return~(a|b|c|d);

(removed the white-space so it looks more terse)