Arithmetic Expression Evaluator

You are given an arithmetic expression as a string. Your task is to evaluate the expression following the standard order of operations, namely PEMDAS/BODMAS.

The expression may include non-negative integers, the operators +, -, *, /, and parentheses ( ). You must ensure that the expression contains only valid characters. Any expression containing invalid characters should result in the output Invalid characters in the expression.

If the expression attempts to divide by zero, output Division by zero error. Similarly, if the expression has a syntax error (for example, missing operands or misplaced operators), output Syntax error in the expression.

For operator precedence, note that the evaluation follows the rules: $$ \text{Expression} = \text{Term} \;\pm\; \text{Term} $$ $$ \text{Term} = \text{Factor} \;\times\/\; \text{Factor} $$ $$ \text{Factor} = \text{Number} \;\text{or}\; (\text{Expression}) $$

Implement your solution so that it reads the input from standard input (stdin) and writes the result to standard output (stdout).

inputFormat

The input consists of a single line containing the arithmetic expression string. The string may include digits, spaces, and the following characters: +, -, *, /, (, ).

outputFormat

Output a single line which is the result of the evaluated expression. If an error is encountered, output one of the following messages exactly:

• Division by zero error
• Invalid characters in the expression
• Syntax error in the expression

2 + 3

5