Java ternary operator confusion -


here code 

public class binarysearch {     public static int binsearch(int key, int[] a)     {         int lo = 0;         int hi = a.length - 1;         while (lo < hi)         {             int mid = (lo + hi) >> 1;             key < a[mid] ? hi = mid : lo = (mid + 1);         }         return lo--;      } }

i got error when compiling 

exception in thread "main" java.lang.error: unresolved compilation problems:      syntax error on tokens, expression expected instead     syntax error on token "]", delete token     syntax error, insert "]" complete expression

and if change '<' '>' as

key > a[mid] ? hi = mid : lo = (mid + 1);

got total different error:

exception in thread "main" java.lang.error: unresolved compilation problem:      syntax error on token ">", -> expected

i confused ternary operator usage in java. after all, code works fine in c++

the compiler having hard time parsing expression because used statement-expression.

since ternary operator expression, should not* used in place of statement. since control assignment, statement, condition, should use regular if:

if (key < a[mid]) {     hi = mid; } else {     lo = (mid + 1); )

* in fact, java not allow ternary expressions used statements. work around issue wrapping expression in assignment or initialization (see demo), result in code hard read , understand, should avoided.


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