Understanding Solidity expressions

An expression refers to a statement (comprising multiple operands and, optionally, zero or more operators) that results in a single value, object, or function. The operand can be a literal, variable, function invocation, or another expression itself.

An example of an expression is as follows:

Age > 10

In the preceding example, Age is a variable, and 10 is an integer literal. Age and 10 are operands, and the > (greater than) symbol is the operator. This expression returns a single Boolean value (true or false), depending on the value stored in Age.

Expressions can be more complex comprising multiple operands and operators, as follows:

((Age > 10) && (Age < 20)) || ((Age > 40) && (Age < 50))

In the preceding code, there are multiple operators in play. The && operator acts as an AND operator between two expressions, which in turn comprises operands and operators. There is also an OR operator...