Infix to prefix conversion example – Infix to prefix conversion using stack – DSA Course Playlist

✅ Step-by-Step: Infix to Prefix Conversion

📘 Goal: Convert an expression like (A + B) * C into * + A B C

🔧 Rules (Similar to Postfix, but slightly different):

1. Reverse the infix expression
   • Swap every ( with ) and vice versa.
2. Convert the reversed infix to postfix
   • (Use the same rules we learned earlier)
3. Reverse the resulting postfix
   • That gives the prefix expression!

💡 Example: Infix → Prefix

Infix Expression:
(A + B) * C

🔹 Step 1: Reverse the Infix Expression

Original: (A + B) * C
Reversed: C * (B + A)

(Swapped ( with ) and reversed order)

🔷 Step 2: Convert Reversed Infix to Postfix

Now convert C * ( B + A ) to postfix:

• C → output → C
• * → push → *
• ( → push
• B → output → C B
• + → push
• A → output → C B A
• ) → pop till ( → C B A +
• * remains → C B A + *

🔹 Step 3: Reverse the Postfix → Prefix

Postfix: C B A + *
Reverse: * + A B C

✅ Final Answer:

Prefix Expression: * + A B C

📌 Summary of Steps:

Step	Action
1	Reverse the infix expression
2	Convert to postfix
3	Reverse the postfix to get prefix