{% extends 'main_index.html' %}
{% block MDesc %}
    Convert prefix expression to postfix expression by entering expression.
{% endblock %}
{% block MKW %}prefix to postfix calculator,prefix to postfix conversion,how to convert prefix to postfix?,prefix to
    postfix evaluator,prefix to postfix converter,prefix expression converter{% endblock %}
{% block Mr %}
    26/12/2020
{% endblock %}
{% block MAut %}
    Amar khamkar
{% endblock %}
{% block title %} prefix to postfix converter
{% endblock %}
{% block body %}
<div class="container text-light">
    <div class="row ">
        <div class="col-md-7 my-3 " style="background-color:rgb(30,30,30);
box-shadow:13px 4px 19px 7px rgb(19 17 17);">
            <div class="my-4 ">
                <h1 class="my-2 text-center text-light">prefix to postfix converter</h1>
                <hr class="bg-dark">
                <h3 class="text-center text-light my-2">What is prefix and postfix expression?</h3>
                <p class="text-light text-monospace my-4 mx-2">An <b>prefix</b> expression
                    is a expression in which first operator comes and proceded by strings. Every prefix string
                    longer than
                    a single variable contains first and
                    second operands followed by an operator.e.g. <b>A,+A B ,*A B ,+ * A B/ C D</b>.</p>
                <p class="text-light text-monospace my-4 mx-2">An postfix expression (also called Reverse Polish
                    Notation)
                    is a single letter or an operator, preceded by two postfix strings. Every postfix string longer
                    than a single variable contains first and
                    second operands followed by an operator.e.g. <b>A,A B +,A B + C D –</b></p>
                <form>
                    <div class="form-group text-light my-4">
                        <label for="exampleInputEmail1">prefix expression</label>
                        <input type="text" class="form-control form-component" placeholder="Enter prefix expression" id="prefix" required>
                    </div>
                    <div class="form-group text-light">
                        <label for="exampleInputPassword1">postfix expression</label>
                        <input type="text" class="form-control form-component" placeholder="postfix expression is..."  id="postfix" readonly>
                    </div>
                    <div>
                        <button type="submit" class="btn btn-outline-secondary text-light con my-3">Convert</button>
                    </div>
                </form>
                <hr class="bg-dark my-2">
                <h3 class="text-center text-light my-4">Conversion from prefix to postfix expressions.</h3>
                <p class="text-light text-monospace my-4 mx-2">
                    First,Read the Prefix expression in reverse order (from right to left)<br>
                    1.If the symbol is an operand, then push it into the Stack<br>
                    2.But if the character is an operator, pop the top two values from stack. <br>
                    3.Create a string by concatenating the two operands and the operator between them.
                    string = (2nd top value+1st top value+operator) <br>
                    4.And push the resultant string back to Stack
                    Repeat the above steps until end of Prefix expression..Checkout examples that are mention below
                    in table.And you can also check
                    <a href="/Conversion/postfix_to_prefix"> postfix to prefix Converter</a> and <a
                        href="/Conversion/postfix_to_postfix"> postfix to posfix Converter</a>
                    Checkout examples that are mention below.</p>
                <div class="container  mt-4"
                     style="background-color: #1d1c1c; border:2px solid white;border-radius: 10px;">
                    1. Prefix Expression:+AB<br>
                    postfix Expression: AB+<br><br>
                    2. Prefix Expression: *CD<br>
                    postfix Expression: CD*<br><br>
                    3. Prefix Expression: *+AB+CD<br>
                    postfix Expression: AB+CD+*<br>
                </div>
                <hr class="bg-dark my-3">
                <h3 class="text-center text-light">Applications</h3>
                <p class="text-light text-monospace my-2 mx-2">Since some compilers,editors calculators convert
                    expression to postfix to evaluate an expression.
                    That's why if it has prefix expression that should be converted to postfix due to their further
                    evaluation. So,this type of converter
                    can be helpful in such cases.
                <p>
            </div>
        </div>
        <div class="col-md-4 my-4 ">
            <div class="col p-4 d-flex flex-column position-static " style="background-color:rgb(30,30,30);
box-shadow:13px 4px 19px 7px rgb(19 17 17);">
                <h4 class="mb-2 ">Converters</h4>
                {% for link in link_string1 %}
                    <li class="my-2"><a href="{{ link.0 }}">{{ link.1 }}</a></li>
                {% endfor %}
            </div>
            <div class="col my-3 p-4 d-flex flex-column position-static " style="background-color:rgb(30,30,30);
box-shadow:13px 4px 19px 7px rgb(19 17 17);">
                <h4 class="my-2">Calculators</h4>
                {% for link in link_string2 %}
                    <li class="my-2"><a href="{{ link.0 }}">{{ link.1 }}</a></li>
                {% endfor %}
            </div>
        </div>
    </div>
</div>
{% endblock %}
{% block JS %}
    <script>
        $('.con').click(function (e) {
            let prefix = document.getElementById("prefix").value;
            let stack = [], str;
            prefix = removeExtraSpaces(prefix);
            for (let i = prefix.length - 1; i >= 0; i--) {
                if (isOperator(prefix[i])) {
                    let op1 = stack.pop();
                    let op2 = stack.pop();
                    if (op1 === undefined || op2 === undefined) {
                        document.getElementById("postfix").value = "Invalid Expression";
                        return;
                    }
                    str = op1 + op2 + prefix[i];
                    stack.push(str)
                } else {
                    stack.push(prefix[i])
                }
            }
            document.getElementById("postfix").value = stack.pop();
            e.preventDefault();
        });
    </script>
{% endblock %}