Merge pull request codemistic#483 from ManikSingh29/Manik

Added Infix to Postfix

Author: gantavyamalviya

Java/Stack/InfixToPostfix@java/InfixToPostfix_byManik.class

@@ -0,0 +1,58 @@
+import java.util.Stack;
+import java.util.Scanner;
+public class InfixToPostfix_byManik {
+
+ static int precedence(char c){
+ switch (c){
+ case '+':
+ case '-':
+ return 1; //Since '+'&'-' are of same precedence 
+ case '*':
+ case '/':
+ return 2;
+ case '^':
+ return 3;
+ }
+ return -1;
+ }
+
+ static String infixToPostFix(String expression){
+
+ String result = "";
+ Stack<Character> stack = new Stack<>();
+ for (int i = 0; i <expression.length() ; i++) {
+ char c = expression.charAt(i);
+
+ //check if char is operator
+ if(precedence(c)>0){
+ while(stack.isEmpty()==false && precedence(stack.peek())>=precedence(c)){
+ result += stack.pop();
+ }
+ stack.push(c);
+ }else if(c==')'){
+ char x = stack.pop();
+ while(x!='('){
+ result += x;
+ x = stack.pop();
+ }
+ }else if(c=='('){
+ stack.push(c);
+ }else{
+ //character is neither operator nor ( 
+ result += c;
+ }
+ }
+ for (int i = 0; i <=stack.size() ; i++) {
+ result += stack.pop();
+ }
+ return result;
+ }
+
+ public static void main(String[] args) {
+ Scanner sc=new Scanner(System.in);
+ System.out.println("Enter the Expression");
+ String Input=sc.next();
+ System.out.println("Infix Expression: " + Input);
+ System.out.println("Postfix Expression: " + infixToPostFix(Input));
+ }
+}