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Engineering LibreTexts

2.10: Assignment

  • Page ID
    10606
  • Overview

    An assignment statement sets and/or re-sets the value stored in the storage location(s) denoted by a variable name; in other words, it copies a value into the variable.[1]

    Discussion

    The assignment operator allows us to change the value of a modifiable data object (for beginning programmers this typically means a variable). It is associated with the concept of moving a value into the storage location (again usually a variable). Within most programming languages the symbol used for assignment is the equal symbol. But bite your tongue, when you see the = symbol you need to start thinking: assignment. The assignment operator has two operands. The one to the left of the operator is usually an identifier name for a variable. The one to the right of the operator is a value.

    Simple Assignment

    age = 21

    The value 21 is moved to the memory location for the variable named: age. Another way to say it: age is assigned the value 21.

    Assignment with an Expression

    total_cousins = 4 + 3 + 5 + 2

    The item to the right of the assignment operator is an expression. The expression will be evaluated and the answer is 14. The value 14 would be assigned to the variable named: total_cousins.

    Assignment with Identifier Names in the Expression

    students_period_1 = 25
    students_period_2 = 19
    total_students = students_period_1 + students_period_2;

    The expression to the right of the assignment operator contains some identifier names. The program would fetch the values stored in those variables; add them together and get a value of 44; then assign the 44 to the total_students variable.

    Key Terms

    assignment
    An operator that changes the value of a modifiable data object.