brackets_validator

• Declare a character stack which will hold an array of all the opening parenthesis.
• Now traverse the expression string exp.
• If the current character is a starting bracket (‘(‘ or ‘{‘ or ‘[‘) then push it to stack.
• If the current character is a closing bracket (‘)’ or ‘}’ or ‘]’) then pop from stack and if the popped character is the matching starting bracket then fine else parenthesis are not balanced.
• After complete traversal, if there is some starting bracket left in stack then “not balanced