Expressions
An expression is a combination of variables, constants, and operators.
Examples:
SI=P*T*R/100 (a+b) c/d; a*b+c (d+x); 5*a+b+b*c; (a+b)*(x+y);
Evaluation of expressions:
An expression can be evaluated based on the precedence of operators, after the evaluation of an expression, the value of the expression is assigned to the variable.
Precedence of operators:
Operator precedence determines which operator will be performed first in a group of operators with different precedence.
- An arithmetic expression without parenthesis will be executed from left to right using the rules of precedence of operators
Highest Presidency :(,),*, /, %
Lowest Presidency: +, –
For instance, 5 + 3 * 2 is calculated as 5 + (3 * 2), giving 11, and not as (5 + 3) * 2, giving 16.
- During the first pass the highest priority operator (if any) are applied as they are encountered.
- Whenever parenthesis is used in the expressions, within parenthesis assumes the highest priority.
- If two or more sets of parenthesis appear one after the another as 9- 12/(3+3)*(2-1). The expression contained in the left-most set is evaluated first and the rightmost set in the last.
Example:
9-12/ (3+3)*(2-1) 9-12/6*1 9-2*1 9-2 7
- If the parenthesis is nested and in such cases evaluation of the expression will process outwards from the innermost set of the parenthesis.
Example:
9-(12/ ((3+3)*2)-1 9-(12/6*2)-1 9-(2*2)-1 9-4-1 5-1 4