Just switched to Java from php
I encountered following issue
I want to rewrite
if(usrname.equals(username) && (passwd.equals(password))){
return true;
}
else{
return false;
}
as
(usrname.equals(username) && passwd.equals(password) )? return true : return false;
it is not working(syntax error) however,
int a=1;
int b=2;
int minVal = a < b ? a : b;
is working
Why ternary operator are not behaving correctly while returning value depending on some condition
EDIT
return (usrname.equals(username) && passwd.equals(password));
could be solution if it return boolean .
lets say i need
(usrname.equals(username) && passwd.equals(password) )? return "member": return "guest";
The first operand in java ternary operator should be a boolean or a statement with boolean result. If the first operand is true then java ternary operator returns second operand else it returns third operand.
In a ternary operator, we cannot use the return statement.
Java ternary operator is the only conditional operator that takes three operands. It's a one-liner replacement for the if-then-else statement and is used a lot in Java programming. We can use the ternary operator in place of if-else conditions or even switch conditions using nested ternary operators.
You can do
return (usrname.equals(username) && passwd.equals(password) )? true : false;
true
and false
can be replaced by any return value you want. If it is just boolean then you can avoid ternary operator altogether. Just do
return (usrname.equals(username) && passwd.equals(password));
lets say I need
(usrname.equals(u) && passwd.equals(p)) ? return "member" : return guest";
The correct syntax is:
return (usrname.equals(u) && passwd.equals(p)) ? "member" : "guest";
The general form of the ternary operator is
expression-1 ? expression-2 : expression-3
where expression-1
has type boolean
, and expression-2
and expression-3
have the same type1.
In your code, you were using return
statements where expressions are required. In Java, a return
statement is NOT a valid expression.
1 - This doesn't take account of the conversions that can take. For the full story, refer to the JLS.
Having said that, the best way to write your example doesn't uses the conditional operator at all:
return usrname.equals(username) && passwd.equals(password);
Why redundant boolean
Just use
return (usrname.equals(username) && passwd.equals(password));
By the way you can simplify:
return (usrname.equals(username) && passwd.equals(password) )? return true : return false;
To:
return usrname.equals(username) && passwd.equals(password);
The ternary operator work similar in php than Java, I think you have made a silly mistake, maybe "username" have a space or another white character
String a1 = "a";
String b1 = "b";
String a2 = "a";
String b2 = "b";
System.out.println((a1.equals(a2)&&b1.equals(b2))?"true":"false");
it return "true"
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