Update Values with Compound Assignment Operators

In this problem, you will create a program that reads an initial value and three operation amounts (add, subtract, multiply) from standard input, then updates the value in sequence using +=, -=, and *= compound assignment operators, printing the result after each operation.

Input Format:

initialValue
addAmount
subAmount
mulAmount

Output Format:

After +=: <value after addition>
After -=: <value after subtraction>
After *=: <value after multiplication>

Learning Objectives:

• Understand how compound assignment operators (+=, -=, *=) work
• Write concise code that combines an operation and assignment in one step
• Apply the idioms commonly used in loops and accumulators