Memory allocation in Blockchain / Solidity - Mini Project: Build & Apply

Memory Allocation in Blockchain Smart Contracts

📖 Scenario: You are building a simple smart contract that stores user balances on a blockchain. Efficient memory allocation is important to keep the contract lightweight and fast.

🎯 Goal: Create a smart contract that initializes user balances, sets a maximum allowed balance, updates balances using a loop, and finally outputs the updated balances.

📋 What You'll Learn

Create a dictionary called balances with exact entries for three users and their initial balances

Create a variable called max_balance and set it to 1000

Use a for loop with variables user and balance to iterate over balances.items() and increase each balance by 100 without exceeding max_balance

Print the final balances dictionary

💡 Why This Matters

🌍 Real World

Smart contracts on blockchains often manage user balances and must allocate memory efficiently to avoid high costs and slow execution.

💼 Career

Understanding memory allocation and safe updates in smart contracts is essential for blockchain developers to write secure and efficient code.

1

DATA SETUP: Create initial user balances

Create a dictionary called balances with these exact entries: 'Alice': 500, 'Bob': 750, 'Charlie': 300

Blockchain / Solidity

# Create the balances dictionary with initial values
# Your code here

Need a hint?

Use curly braces {} to create a dictionary with keys as user names and values as their balances.

2

CONFIGURATION: Set maximum allowed balance

Create a variable called max_balance and set it to 1000

Blockchain / Solidity

balances = {'Alice': 500, 'Bob': 750, 'Charlie': 300}
# Set the maximum allowed balance
# Your code here

Need a hint?

Just assign the number 1000 to the variable max_balance.

3

CORE LOGIC: Increase balances safely

Use a for loop with variables user and balance to iterate over balances.items(). Increase each balance by 100 but do not let it exceed max_balance. Update the balances dictionary accordingly.

Blockchain / Solidity

balances = {'Alice': 500, 'Bob': 750, 'Charlie': 300}
max_balance = 1000
# Increase each balance by 100 without exceeding max_balance
# Your code here

Need a hint?

Use a loop to go through each user and balance. Add 100, then check if it goes over max_balance. If yes, set it to max_balance.

4

OUTPUT: Display updated balances

Write print(balances) to display the updated balances dictionary

Blockchain / Solidity

balances = {'Alice': 500, 'Bob': 750, 'Charlie': 300}
max_balance = 1000
for user in balances:
    new_balance = balances[user] + 100
    if new_balance > max_balance:
        new_balance = max_balance
    balances[user] = new_balance
# Print the balances dictionary
# Your code here

Need a hint?

Use the print() function to show the final dictionary.