The term expression relates to computer programming. Expression is a recognizable combination of symbols that represents a value. Put another way, an expression is any piece of program code that produces a value if properly executed.

The combination of symbols must be permitted by the rules of the particular program. For example, in the C language x + 5 is an expression, as is the arrangement of characters "HUMANS."

An expression has components. There must be at least one operand and one or more operators. An operand is the object that is being manipulated or acted upon. An operator is a symbol that represents the specific action being invoked on an object. For example in the expression x + 5, x and 5 are operands and + is an operator.

In addition to operators and operands, most programming languages, expressions consist of constants, variables, functions, and the use of parentheses. These can be combined...