Expressions in C++

An expression is a combination of variables, constants and operators arranged according to syntax of the language. Some examples of expressions are:

c = (m + n) * (a - b);

temp = (a + b + c) / (d - c);

Expression is evaluated by using assignment statement.

Such a statement is of the form

                 variable = Expression;

The expression on the L.H.S is evaluated first, then the value is assigned to the variable. But all the relevant variables must be assigned the values before the evaluation of the expression.

Evaluation of Expression

By using assignment statement we can evaluate an expression.

variable=expression;

The expression is evaluated first and then a value is assigned to the variable on the left hand side.

e.g.:         temp = ( ( f * cos ( x ) / sin ( y ) ) + ( g * sin ( x ) / cos ( y ) ) )

All relevant variables must be assigned values before the evaluation of the expression.