Determining even/odd numbers (integers)?
开发者_JAVA技巧I feel stupid asking such a simple question, but is there an easy way to determine whether an Integer is even or odd?
if ((n % 2) == 0) {
// number is even
}
else {
// number is odd
}
It's not android specific, but a standard function would be:
boolean isOdd( int val ) { return (val & 0x01) != 0; }
Many compilers convert modulo (%
) operations to their bitwise counterpart automatically, but this method is also compatible with older compilers.
You can use modular division (technically in Java it acts as a strict remainder operator; the link has more discussion):
if ( ( n % 2 ) == 0 ) {
//Is even
} else {
//Is odd
}
If you do a bitwise-and with 1
, you can detect whether the least significant bit is 1. If it is, the number is odd, otherwise even.
In C-ish languages, bool odd = mynum & 1;
This is faster (performance-wise) than mod
, if that's a concern.
When somehow %
as an operator doesn't exist, you can use the AND operator:
oddness = (n & 1) ? 'odd' : 'even'
Similar to others, but here's how I did it.
boolean isEven = i %2 ==0;
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