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Java/DSA1.java

@@ -0,0 +1,239 @@
+package DSA;
+import java.awt.*;
+import javax.swing.*;
+import java.awt.event.*;
+import java.util.*;
+public class DSA1 {
+    static int precedence(char c){
+        switch (c){
+            case '+':
+            case '-':
+                return 1;
+            case '*':
+            case '/':
+                return 2;
+            case '^':
+                return 3;
+        }
+        return -1;
+    }
+
+    public static StringBuilder infixToPreFix(String expression){
+
+        StringBuilder result = new StringBuilder();
+        StringBuilder input = new StringBuilder(expression);
+        input.reverse();
+        Stack<Character> stack = new Stack<>();
+
+        char [] charsExp = new String(input).toCharArray();
+        for (int i = 0; i < charsExp.length; i++) {
+
+            if (charsExp[i] == '(') {
+                charsExp[i] = ')';
+                i++;
+            }
+            else if (charsExp[i] == ')') {
+                charsExp[i] = '(';
+                i++;
+            }
+        }
+        for (int i = 0; i <charsExp.length ; i++) {
+            char c = charsExp[i];
+
+            //check if char is operator or operand
+            if(precedence(c)>0){
+                while(stack.isEmpty()==false && precedence(stack.peek())>=precedence(c)){
+                    result.append(stack.pop());
+                }
+                stack.push(c);
+            }else if(c==')'){
+                char x = stack.pop();
+                while(x!='('){
+                    result.append(x);
+                    x = stack.pop();
+                }
+            }else if(c=='('){
+                stack.push(c);
+            }else{
+
+                result.append(c);
+            }
+        }
+
+        for (int i = 0; i <=stack.size() ; i++) {
+            result.append(stack.pop());
+        }
+        return result.reverse();
+    }
+    public String infixToPostfix(String s) {
+        String postfix = "";
+        Stack<Character> st = new Stack<Character>();
+        char ch[] = s.toCharArray();
+        for (char c : ch) {
+            if (c != '+' && c != '-' && c != '*' && c != '/' && c != '(' && c != ')') {
+                postfix = postfix + c;
+            } else if (c == '(') {
+                st.push(c);
+            } else if (c == ')') {
+                while (!st.isEmpty()) {
+                    char t = st.pop();
+                    if (t != '(') {
+                        postfix = postfix + t;
+                    } else {
+                        break;
+                    }
+
+                }
+
+            } else if (c == '+' || c == '-' || c == '*' || c == '/') {
+                if (st.isEmpty()) {
+                    st.push(c);
+                }
+                else {
+                    while (!st.isEmpty()) {
+                        char t = st.pop();
+                        if (t == '(') {
+                            st.push(t);
+                            break;
+                        }
+                        else if (c == '+' || c == '-' || c == '*' || c == '/') {
+                            if (getPriority(t) < getPriority(c)){
+                                st.push(t);
+                                break;
+                            }
+                            else{
+                                postfix = postfix+ t;
+                            }
+                        }
+                    }
+                    st.push(c);
+                }
+             }
+
+         }
+        while (!st.isEmpty()){
+            postfix = postfix+ st.pop();
+        }
+        return (postfix);
+    }
+
+
+    public int getPriority(char c){
+        if (c=='+' || c=='-'){
+            return 1;
+        }
+        else {
+            return 2;
+        }
+    }
+    public static void main(String[] args) {
+        A obj1= new A();
+        DSA1 o = new DSA1();
+        String s1 ="a+b*(a*b-c)";
+        System.out.println(o.infixToPostfix(s1));
+        System.out.println(obj1.infixToPrefix(s1));
+
+        Frame f = new Frame("INFIX TO PREFIX & POSTFIX");
+        f.setBounds(0,0,500,500);
+        f.setSize(500,500);
+
+        f.setBackground(Color.black);
+        f.setVisible(true);
+        f.setLayout(null);
+        JPanel p = new JPanel();
+        ImageIcon background=new ImageIcon("");
+        Image img=background.getImage();
+        Image temp=img.getScaledInstance(500,500,Image.SCALE_SMOOTH);
+        background=new ImageIcon(temp);
+        JLabel back=new JLabel(background);
+        back.setLayout(null);
+        back.setBounds(0,0,500,500);
+        p.setBounds(0,0,500,500);
+        p.add(back);
+        f.add(p);
+
+        Label l1 = new Label("CONVERT INFIX TO PREFIX & POSTFIX");
+        l1.setAlignment(Label.CENTER);
+        l1.setBounds(100,100,300,30);
+        l1.setBackground(Color.pink);
+        p.add(l1);
+
+        Label l2 = new Label("Enter the expression");
+        l2.setBounds(60,180,160,30);
+        l2.setBackground(Color.pink);
+        l2.setAlignment(Label.CENTER);
+        p.add(l2);
+
+        TextField t1 = new TextField();
+        t1.setBounds(270,180,160,30);
+        t1.setBackground(Color.pink);
+        p.add(t1);
+
+        Label l3= new Label();
+        l3.setBounds(140,340,220,30);
+        l3.setBackground(Color.pink);
+        p.add(l3);
+
+        Button b1 = new Button("convert to postfix");
+        b1.setBackground(Color.pink);
+        b1.setBounds(280,260,130,30);
+        p.add(b1);
+
+        Button b2 = new Button("convert to prefix");
+        b2.setBackground(Color.pink);
+        b2.setBounds(90,260,130,30);
+        p.add(b2);
+
+        b1.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                l3.setText(o.infixToPostfix(t1.getText()));
+            }
+        });
+        b2.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                String st = t1.getText();
+                l3.setText(String.valueOf(infixToPreFix(st.toString())));
+            }
+        });
+
+        f.addWindowListener(new WindowListener() {
+            @Override
+            public void windowOpened(WindowEvent e) {
+
+            }
+
+            @Override
+            public void windowClosing(WindowEvent e) {
+            f.dispose();
+            }
+
+            @Override
+            public void windowClosed(WindowEvent e) {
+
+            }
+
+            @Override
+            public void windowIconified(WindowEvent e) {
+
+            }
+
+            @Override
+            public void windowDeiconified(WindowEvent e) {
+
+            }
+
+            @Override
+            public void windowActivated(WindowEvent e) {
+
+            }
+
+            @Override
+            public void windowDeactivated(WindowEvent e) {
+
+            }
+        });
+    }
+    }
+