Add day40

Author: MadhavBahl

README.md

@@ -67,6 +67,7 @@ Motivate yourself to code daily till 60 days, and see the magic! Coding will bec
 | [Day 37](./day37) | [Radix Sort](./day37) | [http://codetoexpress.tech/dc/day37/](http://codetoexpress.tech/dc/day37/) | **Misc** |
 | [Day 38](./day38) | [Implement Stack Data Structure](./day38) | [http://codetoexpress.tech/dc/day38/](http://codetoexpress.tech/dc/day38/) | **Beginner** |
 | [Day 39](./day39) | [Maximum Element and Reverse Stack](./day39) | [http://codetoexpress.tech/dc/day39/](http://codetoexpress.tech/dc/day39/) | **Intermediate** |
+| [Day 40](./day40) | [Prefix, Infix, Postfix Conversion](./day40) | [http://codetoexpress.tech/dc/day40/](http://codetoexpress.tech/dc/day40/) | **Intermediate** |
 
 ## [More Problems](./BONUS/README.md)
 

day39/Daily Codes.png

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+// to be added

day39/cover.png

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+// To Be Added

day40/JavaScript/inToPost.js

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+// To Be added

day40/JavaScript/inToPre.js

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+![cover](./cover.png)
+
+# Day 40 - Prerfix, Infix, Postfix Conversion
+
+**Infix Expression**: The expression of the form a op b. When an operator is in-between every pair of operands.
+**Example**: ( (A * B) + (C / D) )	
+
+**Prefix Operation**: An expression is called the prefix expression if the operator appears in the expression before the operands. Simply of the form (operator operand1 operand2)
+**Example**: (+ (* A B) (/ C D) )
+
+**Postfix Expression**: The expression of the form a b op. When an operator is followed for every pair of operands.
+**Example**: ( (A B *) (C D /) +)
+
+## Question 1 
+
+Convert an Infix Expression to a Postfix Expression
+
+**Hint**: https://www.geeksforgeeks.org/stack-set-2-infix-to-postfix/
+
+## Question 2
+
+Convert an Infix Expression to a Prefix Expression
+
+**Hint**: https://www.geeksforgeeks.org/infix-to-prefix-conversion-using-two-stacks/
+
+## Question 3
+
+Convert an Postfix Expression to a Infix Expression
+
+**HINT**: https://www.geeksforgeeks.org/postfix-to-infix/
+
+## Solution to Question 1
+
+### [JavaScript Implementation](./JavaScript/inToPost.js)
+
+```js
+// To Be Added
+```
+
+## Solution to Question 2
+
+### [JavaScript Implementation](./JavaScript/inToPre.js)
+
+```js
+// To Be Added
+```
+
+## Solution to Question 3
+
+### [JavaScript Implementation](./JavaScript/postToIn.js)
+
+```js
+// To Be Added
+```