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by kevinwang 3420 days ago
Is "bool(a1) + ... + bool(aN) == M" not just "a1 || a2...||an"?
2 comments
kmill 3420 days ago
No, it's true when exactly M are true. "a1 || a2 || ... || an" is true when at least one is true.

The latter is the same as "a1 + ... + an == 1 || a1 + ... + an == 2 || ... || a1 + ... + an == n".

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Ded7xSEoPKYNsDd 3420 days ago
So your + operator implicitly casts booleans to an integer type, with false=0 and true=1?
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kmill 3420 days ago
What you are saying is the only way I can imagine to interpret what I wrote, if one assumes I was intending to make any sense.

By the way, in Python, bool is a subtype of int (i.e., instanceof(True,int) == True), and True + True == 2. C is the same, and in Javascript booleans are converted to integers for arithmetic operations.

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OJFord 3420 days ago
> What you are saying is the only way I can imagine to interpret what I wrote

One might imagine it (without experience, or not thinking, of any particular programming language) as being a logical OR on Booleans - which in EE at least is frequently written '+'.

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simcop2387 3420 days ago
In c++, yes. Not every language will do that though.
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ambrop7 3420 days ago
Obviously no, the first (for M==1) means exactly one is true, the latter at least one is true. But a1||...||aN is equivalent to bool(a1)+...+bool(aN)>0 (assuming no integer overflow :).
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