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Assignment operators

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expression assignment-operator expression

assignment-operator : one of   =   *=   /=   %=   +=   -=   <<=   >>=   &=   ^=   |=

Assignment operators store a value in the object specified by the left operand. There are two kinds of assignment operations:

simple assignment , in which the value of the second operand is stored in the object specified by the first operand.

compound assignment , in which an arithmetic, shift, or bitwise operation is performed before storing the result.

All assignment operators in the following table except the = operator are compound assignment operators.

Assignment operators table

Operator keywords.

Three of the compound assignment operators have keyword equivalents. They are:

C++ specifies these operator keywords as alternative spellings for the compound assignment operators. In C, the alternative spellings are provided as macros in the <iso646.h> header. In C++, the alternative spellings are keywords; use of <iso646.h> or the C++ equivalent <ciso646> is deprecated. In Microsoft C++, the /permissive- or /Za compiler option is required to enable the alternative spelling.

Simple assignment

The simple assignment operator ( = ) causes the value of the second operand to be stored in the object specified by the first operand. If both objects are of arithmetic types, the right operand is converted to the type of the left, before storing the value.

Objects of const and volatile types can be assigned to l-values of types that are only volatile , or that aren't const or volatile .

Assignment to objects of class type ( struct , union , and class types) is performed by a function named operator= . The default behavior of this operator function is to perform a member-wise copy assignment of the object's non-static data members and direct base classes; however, this behavior can be modified using overloaded operators. For more information, see Operator overloading . Class types can also have copy assignment and move assignment operators. For more information, see Copy constructors and copy assignment operators and Move constructors and move assignment operators .

An object of any unambiguously derived class from a given base class can be assigned to an object of the base class. The reverse isn't true because there's an implicit conversion from derived class to base class, but not from base class to derived class. For example:

Assignments to reference types behave as if the assignment were being made to the object to which the reference points.

For class-type objects, assignment is different from initialization. To illustrate how different assignment and initialization can be, consider the code

The preceding code shows an initializer; it calls the constructor for UserType2 that takes an argument of type UserType1 . Given the code

the assignment statement

can have one of the following effects:

Call the function operator= for UserType2 , provided operator= is provided with a UserType1 argument.

Call the explicit conversion function UserType1::operator UserType2 , if such a function exists.

Call a constructor UserType2::UserType2 , provided such a constructor exists, that takes a UserType1 argument and copies the result.

Compound assignment

The compound assignment operators are shown in the Assignment operators table . These operators have the form e1 op = e2 , where e1 is a non- const modifiable l-value and e2 is:

an arithmetic type

a pointer, if op is + or -

a type for which there exists a matching operator *op*= overload for the type of e1

The built-in e1 op = e2 form behaves as e1 = e1 op e2 , but e1 is evaluated only once.

Compound assignment to an enumerated type generates an error message. If the left operand is of a pointer type, the right operand must be of a pointer type, or it must be a constant expression that evaluates to 0. When the left operand is of an integral type, the right operand must not be of a pointer type.

Result of built-in assignment operators

The built-in assignment operators return the value of the object specified by the left operand after the assignment (and the arithmetic/logical operation in the case of compound assignment operators). The resultant type is the type of the left operand. The result of an assignment expression is always an l-value. These operators have right-to-left associativity. The left operand must be a modifiable l-value.

In ANSI C, the result of an assignment expression isn't an l-value. That means the legal C++ expression (a += b) += c isn't allowed in C.

Expressions with binary operators C++ built-in operators, precedence, and associativity C assignment operators

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5.4: Arithmetic Assignment Operators

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• Page ID 10264

• Kenneth Leroy Busbee
• Houston Community College via OpenStax CNX

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Overview of Arithmetic Assignment

The five arithmetic assignment operators are a form of short hand. Various textbooks call them "compound assignment operators" or "combined assignment operators". Their usage can be explaned in terms of the assignment operator and the arithmetic operators. In the table we will use the variable age and you can assume that it is of integer data type.

Demonstration Program in C++

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Download the Demo Program

Download and store the following file(s) to your storage device in the appropriate folder(s). Following the methods of your compiler/IDE, compile and run the program(s). Study the soruce code file(s) in conjunction with other learning materials.

Download from Connexions: Demo_Arithmetic_Assignment.cpp

CS101: Introduction to Computer Science I

Assignment operators.

Read this introductory article.

Simple Assignment Operator

The assignment statement is one of the central constructs in programming languages. Using an assignment statement, the programmer can change the binding of values to the variables in the program. In the simple assignment statements listed below, variables x and y are being assigned values 0 and 1 respectively. The variables are of type integer in this case.

int x = 0; int y = 1;

Compound Assignment Operators

The assignment operator can be combined with various arithmetic and logic operators to provide compound assignments where arithmetic and logic operations are part of the assignment operation. The assignment can be combined with the following arithmetic and logic operations (the variable x is of type integer, z is a Boolean vector, and y is of type Boolean in these examples).

Unary Assignment Operators

Java has two special unary arithmetic operators, which are special cases of compound assignment operators. These are the increment and the decrement operators. They combine increment and decrement operations (++ and --) with the assignment operation. For example:

x = ++count;

is equivalent to

count = count + 1; x = count;

Assignment for Object Creation

In object-oriented programming, classes provide a blueprint or a factory for creating objects. An object is an instance of a class. Using the new operation in Java, a programmer can create an instance of an object using the simple assignment operator. For example, if we have a rectangle class that uses length and width attributes, then:

rectangle R1 = new Rectangle(5, 10);

creates a new rectangle object named R1 with length 5 and width 10.

rectangle R2 = new Rectangle(7, 8);

creates another new rectangle object named R2 with length 7 and width 8.

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Assignment Operators in C

In C language, the assignment operator stores a certain value in an already declared variable. A variable in C can be assigned the value in the form of a literal, another variable, or an expression.

The value to be assigned forms the right-hand operand, whereas the variable to be assigned should be the operand to the left of the " = " symbol, which is defined as a simple assignment operator in C.

In addition, C has several augmented assignment operators.

The following table lists the assignment operators supported by the C language −

Simple Assignment Operator (=)

The = operator is one of the most frequently used operators in C. As per the ANSI C standard, all the variables must be declared in the beginning. Variable declaration after the first processing statement is not allowed.

You can declare a variable to be assigned a value later in the code, or you can initialize it at the time of declaration.

You can use a literal, another variable, or an expression in the assignment statement.

Once a variable of a certain type is declared, it cannot be assigned a value of any other type. In such a case the C compiler reports a type mismatch error.

In C, the expressions that refer to a memory location are called "lvalue" expressions. A lvalue may appear as either the left-hand or right-hand side of an assignment.

On the other hand, the term rvalue refers to a data value that is stored at some address in memory. A rvalue is an expression that cannot have a value assigned to it which means an rvalue may appear on the right-hand side but not on the left-hand side of an assignment.

Variables are lvalues and so they may appear on the left-hand side of an assignment. Numeric literals are rvalues and so they may not be assigned and cannot appear on the left-hand side. Take a look at the following valid and invalid statements −

Augmented Assignment Operators

In addition to the = operator, C allows you to combine arithmetic and bitwise operators with the = symbol to form augmented or compound assignment operator. The augmented operators offer a convenient shortcut for combining arithmetic or bitwise operation with assignment.

For example, the expression "a += b" has the same effect of performing "a + b" first and then assigning the result back to the variable "a".

Run the code and check its output −

Similarly, the expression "a <<= b" has the same effect of performing "a << b" first and then assigning the result back to the variable "a".

Here is a C program that demonstrates the use of assignment operators in C −

When you compile and execute the above program, it will produce the following result −

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An operator is symbol that takes one or more values (or expressions, in programming jargon) and yields another value (so that the construction itself becomes an expression) [2] .

There are many different types of operators, but the ones we primarily concern ourselves with are boldfaced below. If you'd like to learn more about different types of operators in PHP, please click here .

• Operator Precedence
• Arithmetic Operators
• Assignment Operators
• Bitwise Operators
• Comparison Operators
• Error Control Operators
• Execution Operators
• Incrementing/Decrementing Operators
• Logical Operators
• String Operators
• Array Operators
• Type Operators
• 1 Assignment operators
• 2 Arithmetic operators
• 3 Comparison operators
• 5 The way the IB wants you to use operators
• 6 Python operators cheatsheet
• 7 Standards
• 8 References

Assignment operators [ edit ]

An assignment operator assigns a value to its left operand based on the value of its right operand. [3]

Arithmetic operators [ edit ]

Arithmetic operators take numerical values (either literals or variables) as their operands and return a single numerical value. The standard arithmetic operators are addition (+), subtraction (-), multiplication (*), and division (/). [4]

An example of some arithmetic operators in PHP can be found below [5] .

An example of some arithmetic operators in Python can be found below [6] .

Comparison operators [ edit ]

Comparison operators, as their name implies, allow you to compare two values. [7]

An example of some conditional operators in PHP can be found below [8] .

An example of some conditional operators in Python can be found below [9] .

A video [ edit ]

This video references the C programming language and scratch, but the ideas about operators are excellent. In the case of conditionals, PHP and C share similar syntax (but not exact).

The way the IB wants you to use operators [ edit ]

Please know all code submitted to the IB (with the exception of object oriented programming option) is in pseudocode . The way we write operators in pseudocode is different than the way we might write them in the real world.

Click here to view a file describing approved notation, including pseudocode This is the approved notation sheet from the IB.

Below is a graphic that is taken from the above PDF file to help you understand how the IB wants operators to look.

Python operators cheatsheet [ edit ]

Click here for an excellent python cheatsheet

Standards [ edit ]

• Define the terms: variable, constant, operator, object.
• Define common operators.
• Analyse the use of variables, constants and operators in algorithms.

References [ edit ]

• ↑ http://www.flaticon.com/
• ↑ http://php.net/manual/en/language.operators.php
• ↑ https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Assignment_Operators
• ↑ https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
• ↑ http://php.net/manual/en/language.operators.arithmetic.php
• ↑ https://www.geeksforgeeks.org/basic-operators-python/
• ↑ https://www.php.net/manual/en/language.operators.comparison.php
• ↑ http://php.net/manual/en/language.operators.comparison.php

A natural number, a negative of a natural number, or zero.

anomalous or exceptional conditions requiring special processing – often changing the normal flow of program execution

Give the precise meaning of a word, phrase, concept or physical quantity.

Break down in order to bring out the essential elements or structure. To identify parts and relationships, and to interpret information to reach conclusions.

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Assignment Operators

Let's take a look at the assignment operator and a few related shorthands.

Introduction

• Compound assignment operators
• Increment and decrement operators

We have already seen the assignment operator, which is used to assign a value to a variable or update its value. The “equal to” sign( = ) is used for this operator. Anything on the right of = is assigned to the variable on its left.

Therefore, you always need to place a variable on the left side of = , whereas on the right side can be a value or another variable. Another thing you need to be careful about is the type. You can assign a double value or another double type variable only to a double type variable.

Let’s look at some use cases of the assignment operator.

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Title: poseidon: efficient foundation models for pdes.

Abstract: We introduce Poseidon, a foundation model for learning the solution operators of PDEs. It is based on a multiscale operator transformer, with time-conditioned layer norms that enable continuous-in-time evaluations. A novel training strategy leveraging the semi-group property of time-dependent PDEs to allow for significant scaling-up of the training data is also proposed. Poseidon is pretrained on a diverse, large scale dataset for the governing equations of fluid dynamics. It is then evaluated on a suite of 15 challenging downstream tasks that include a wide variety of PDE types and operators. We show that Poseidon exhibits excellent performance across the board by outperforming baselines significantly, both in terms of sample efficiency and accuracy. Poseidon also generalizes very well to new physics that is not seen during pretraining. Moreover, Poseidon scales with respect to model and data size, both for pretraining and for downstream tasks. Taken together, our results showcase the surprising ability of Poseidon to learn effective representations from a very small set of PDEs during pretraining in order to generalize well to unseen and unrelated PDEs downstream, demonstrating its potential as an effective, general purpose PDE foundation model. Finally, the Poseidon model as well as underlying pretraining and downstream datasets are open sourced, with code being available at this https URL and pretrained models and datasets at this https URL .

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Understanding the Java Ternary Operator with Examples

Learn how to use the ternary operator in Java with this comprehensive guide. The ternary operator is a concise way to perform conditional operations, simplifying your code and improving readability.

Introduction to the Ternary Operator

The ternary operator in Java is a shorthand for the if-else statement. It is a compact syntax that evaluates a condition and returns one of two values based on the condition's result. The ternary operator is also known as the conditional operator.

Syntax of the Ternary Operator

The basic syntax of the ternary operator is: condition?value if true:value if falsecondition?value if true:value if false

• Condition : An expression that evaluates to either true or false.
• Value if True : The value returned if the condition is true.
• Value if False : The value returned if the condition is false.

Examples of the Ternary Operator

Example 1: basic usage.

Determine the greater of two numbers.

Code Explanation

You can use the ternary operator to compare two numbers and assign the greater number to a variable.

Example 2: Conditional Assignment

Assign a default value to a variable if a condition is not met.

Use the ternary operator to assign a value based on the result of a condition, such as checking if a variable is null or empty.

Example 3: Nested Ternary Operator

Evaluate multiple conditions.

The ternary operator can be nested to handle more complex conditional logic, though readability may suffer.

Advantages of Using the Ternary Operator

Conciseness.

• Code Reduction : The ternary operator can reduce the number of lines of code, making it more concise and easier to read.

Readability

• Simplified Logic : For simple conditions, the ternary operator makes the code more readable by avoiding verbose if-else statements.

Best Practices for Using the Ternary Operator

• Simple Conditions : Use the ternary operator for simple, clear conditions. For complex logic, traditional if-else statements are preferable for better readability.
• Avoid Nesting : Avoid nesting ternary operators as it can make the code difficult to understand and maintain.

Consistency

• Consistent Use : Use the ternary operator consistently in your codebase to maintain a uniform coding style.

Understanding and using the ternary operator effectively can simplify your Java code and make conditional statements more concise and readable.

For a detailed step-by-step guide, visit the full article at https://www.geeksforgeeks.org/java-ternary-operator-with-examples/ .