Unfamiliar Syntax "int x = i1 << 24 | i2 ..."

[KentDMc]

Hi folks,

I'm coming accross a syntax I'm not familiar with and am unable to Google it because of the characters involved...

Here is an example.

int i1, i2, i3, i4;

//set the ints to some values

int x = i1 << 24 | i2 << 16 | i3 << 8 | i4;

I don't understand what that last line is doing. Can anyone explain this?

[Eranga]

In your expression you have three operators, =, << and |. I guess did you know the meaning of each of these.

[xcallmejudasx]

i believe the << is a bit operator meaning shift left and the | works the same as || but for bit manipulation.

[xcallmejudasx]

I was correct. Read up here Bitwise and Bit Shift Operators (The Java™ Tutorials > Learning the Java Language > Language Basics)

the << is the Signed left shift and the | is a bitwise inclusive or. the following truth table explains how your 4 parameters would end up true

p1|p2|p3|p4|'|'|
0 | 0| 0 | 1 |1
0 | 0| 1 | 0 |1
0 | 1| 0 | 0 |1
1 | 0| 0 | 0 |1

any other combination will return false unless you place parentheses around your operators.

[KentDMc]

Thank you for your responses, guys. When I first looked at this I thought it was some kinda of logical shortcut, similar to max = (a > b) ? a : b;

[Eranga]

Actually this is about ternary operator, simplest form of if-else condition. Logical operators are totally different from this.