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Assign variable value inside if-statement [duplicate]
I was wondering whether it is possible to assign a variable a value inside a conditional operator like so:
if((int v = someMethod()) != 0) return v;
Is there some way to do this in Java? Because I know it's possible in while conditions, but I'm not sure if I'm doing it wrong for the if-statement or if it's just not possible.
- That'd be nice. – Josh M. Commented Feb 3, 2022 at 20:57
- You were so preoccupied with whether you could, you didn’t stop to think if you should... That's some real confusing code right there and it can get even worse. You can have this other abomination: if(v = doSomething()) { /* do stuff */ } . By the time you realise that's a = and not == , you already interpreted the code wrong for hours trying to understand why it doesn't work – Guilherme Taffarel Bergamin Commented Mar 3, 2023 at 13:03
9 Answers 9
Variables can be assigned but not declared inside the conditional statement:
- 3 So if you need the declaration anyway just place the someMethod() assign in front of the declaration. int v = someMethod() – wviana Commented Feb 17, 2016 at 19:53
- 3 Pitty, no oneliner for me :( – Pieter De Bie Commented Dec 20, 2016 at 9:02
- 1 i pitty the oneliner >:D – Jason K. Commented Apr 6, 2017 at 16:15
- 16 I pity the int foo . – xdhmoore Commented May 9, 2018 at 22:44
- 2 @wviana In some situations you may not want to run someMethod() and spend run time until after other checks are made in the conditional. If someMethod() takes a long time, and you don't want to check the result of that until a later "else". With your way, that time would be spent on it whether it is used or not. – Michael K Commented Oct 21, 2022 at 15:43
You can assign , but not declare , inside an if :
an assignment returns the left-hand side of the assignment. so: yes. it is possible. however, you need to declare the variable outside:
- 3 As per specification , assignment returns value of the left -hand side (the variable that was assigned to). – StenSoft Commented Mar 12, 2015 at 15:45
- 1 @rmalchow Correction, you don't necessarily have to initialize variable, it depends on what if statement does. If it returns out, for instance, then there is no need for initialization. – randomUser56789 Commented Jul 30, 2015 at 11:24
- @StenSoft - true. however ... i wonder if, other than an implit cast - as in long i = (int)2; - this would have any significance? – rmalchow Commented Jul 23, 2016 at 6:50
- @randomUser56789 can you elaborate? "if((int v = call()) != 4)" just won't work. – rmalchow Commented Jul 23, 2016 at 6:51
- @rmalchow it won't work indeed. I said that you don't have to initialize the variable outside, but you do have to declare it outside. – randomUser56789 Commented Jul 25, 2016 at 7:38
Yes, you can assign the value of variable inside if.
I wouldn't recommend it. The problem is, it looks like a common error where you try to compare values, but use a single = instead of == or === .
It will be better if you do something like this:
- 1 This is easy to shoot yourself in the foot with because it compiles just fine... boolean b = false; if ( b = true ) { //oops } – Edward J Beckett Commented Mar 16, 2018 at 12:52
- @EddieB This isn't like shooting yourself in the foot. More about not knowing the kind of gun you have in your hands. Gosling messed up Java a lot in the name of the former when most of the time it had to do with the latter. – stillanoob Commented Jul 14, 2020 at 9:53
I believe that your problem is due to the fact that you are defining the variable v inside the test. As explained by @rmalchow, it will work you change it into
There is also another issue of variable scope. Even if what you tried were to work, what would be the point? Assuming you could define the variable scope inside the test, your variable v would not exist outside that scope. Hence, creating the variable and assigning the value would be pointless, for you would not be able to use it.
Variables exist only in the scope they were created. Since you are assigning the value to use it afterwards, consider the scope where you are creating the varible so that it may be used where needed.
Yes, it's possible to do. Consider the code below:
I hope this will satisfy your question.
You can assign a variable inside of if statement, but you must declare it first
Yes, it is possible to assign inside if conditional check. But, your variable should have already been declared to assign something.
Because I know it's possible in while conditions, but I'm not sure if I'm doing it wrong for the if-statement or if it's just not possible.
HINT: what type while and if condition should be ??
If it can be done with while, it can be done with if statement as weel, as both of them expect a boolean condition.
Not the answer you're looking for? Browse other questions tagged java or ask your own question .
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Declaration is not to declare "value" to a variable; it's to declare the type of the variable. Assignment is simply the storing of a value to a variable. Initialization is the assignment of a value to a variable at the time of declaration. These definitions also applies to fields. int i; // simple declaration. i = 42 // simple assignment.
Assignment. Assignment in Java is the process of giving a value to a primitive-type variable or giving an object reference to an object-type variable. The equals sign acts as assignment operator in Java, followed by the value to assign. The following sample Java code demonstrates assigning a value to a primitive-type integer variable, which has ...
An assignment statement designates a value for a variable. An assignment statement can be used as an expression in Java. After a variable is declared, you can assign a value to it by using an assignment statement. In Java, the equal sign = is used as the assignment operator. The syntax for assignment statements is as follows: variable ...
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Assignment statements initialize or change the value stored in a variable using the assignment operator =. An assignment statement always has a single variable on the left hand side of the = sign. The value of the expression on the right hand side of the = sign (which can contain math operators and other variables) is copied into the memory ...
An assignment statement designates a value for a variable. An assignment statement can be used as an expression in Java. After a variable is declared, you can assign a value to it by using an assignment statement. In Java, the equal sign (=) is used as the assignment operator. The syntax for assignment statements is as follows:
The Java programming language provides operators that perform addition, subtraction, multiplication, and division. There's a good chance you'll recognize them by their counterparts in basic mathematics. The only symbol that might look new to you is "%", which divides one operand by another and returns the remainder as its result.
Java Assignment Operators. The Java Assignment Operators are used when you want to assign a value to the expression. The assignment operator denoted by the single equal sign =. In a Java assignment statement, any expression can be on the right side and the left side must be a variable name. For example, this does not mean that "a" is equal to ...
The data type of the value returned by an expression depends on the elements used in the expression. The expression cadence = 0 returns an int because the assignment operator returns a value of the same data type as its left-hand operand; in this case, cadence is an int.As you can see from the other expressions, an expression can return other types of values as well, such as boolean or String.
Assignment Statements. An assignment statement uses the assignment operator (=) to assign the result of an expression to a variable.In its simplest form, you code it like this: variable = expression; For example: int a = (b * c) / 4; A compound assignment operator is an operator that performs a calculation and an assignment at the same time. All Java binary arithmetic operators (that is, the ...
Read this chapter, which covers variables and arithmetic operations and order precedence in Java. 9. Assignment Statements. ... An assignment statement changes the value that is held in a variable. The program uses an assignment statement. The assignment statement puts the value 123 into the variable. In other words, while the program is ...
Initialization declaration and assignment terms in Java - A variable provides us with named storage that our programs can manipulate. Each variable in Java has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variab
The assignment operator in Java evaluates to the assigned value (like it does in, e.g., c). So here, readLine() will be executed, and its return value stored in line. That stored value is then checked against null, and if it's null then the loop will terminate.
The assignment statement. The assignment statement is used to store a value in a variable. As in most programming languages these days, the assignment statement has the form: <variable>= <expression>; For example, once we have an int variable j, we can assign it the value of expression 4 + 6: int j; j= 4+6; As a convention, we always place a ...
Simple Assignment Operator (=) To assign a value to a variable, use the basic assignment operator (=). It is the most fundamental assignment operator in Java. It assigns the value on the right side of the operator to the variable on the left side. In the above example, the variable x is assigned the value 10.
Questions 2 and 3 ask about the if-statement and if-else statement. These are the same as in just about any programming language, except for the syntax, of course. So use your knowledge of these statements in whatever programming language you know. 1. Write the algorithm for executing the Java assignment statement <variable>= <expression>; 2.
To execute the assignment statement. x. int. x= x + 2; evaluate the expression x + 2, resulting in the value 7, and store this value in box x. Thus, cross out the value 5 and store the value 7 in the box. Since a variable can hold only one value, the old value is removed. Don't make this mistake.
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Assignment operators are used in programming toassign valuesto variables. We use an assignment operator to store and update data within a program. They enable programmers to store data in variables and manipulate that data. The most common assignment operator is the equals sign (=), which assigns the value on the right side of the operator to ...
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15. You can use java ternary operator, this statement can be read as, If testCondition is true, assign the value of value1 to result; otherwise, assign the value of value2 to result. simple example would be, In above code, if the variable a is less than b, minVal is assigned the value of a; otherwise, minVal is assigned the value of b.
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@rmalchow Correction, you don't necessarily have to initialize variable, it depends on what if statement does. If it returns out, for instance, then there is no need for initialization. - randomUser56789