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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/apursley2012/airgead-investment-calculator/llms.txt

Use this file to discover all available pages before exploring further.

The source/ folder preserves the original Airgead Banking console application written in C++. This is the program that the web version was designed to replicate. The console app accepts the same four inputs and prints two formatted reports — one without monthly deposits and one with.

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Source Files

FilePurpose
airgeadBankingApp.cppEntry point: collects the four inputs and calls the Investment display methods
investment.hDeclares the Investment class, YearlyInvestmentResult struct, and public interface
investment.cppImplements calculation logic and formatted console report output

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Compile and Run

1

Navigate to the source directory

cd source
2

Compile with g++

g++ airgeadBankingApp.cpp investment.cpp -o airgead
3

Run on macOS/Linux

./airgead
4

Run on Windows PowerShell

.\airgead.exe

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Sample Session

The following shows what the console application looks like when run with example inputs: 
**************************************
********* Airgead Banking ************
**************************************
Initial Investment Amount: $5000
Monthly Deposit: $250
Annual Interest (%): 5
Number of years: 5

Balance and Interest Without Additional Monthly Deposits
==================================================================
Year     Year End Balance       Year End Earned Interest
------------------------------------------------------------------
1        $5,255.81                              $255.81
2        $5,524.71                              $268.89
...

Balance and Interest With Additional Monthly Deposits
==================================================================
Year     Year End Balance       Year End Earned Interest
------------------------------------------------------------------
1        $8,374.33                              $374.33
...

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Input Validation

The main loop uses two helper functions to ensure that all user-provided values are valid before constructing the Investment object:
  • readNonNegativeDouble() — used for the starting balance, monthly deposit, and annual interest rate. Repeats the prompt if the input fails to parse or is negative.
  • readPositiveInteger() — used for the number of years. The entered value must be a whole number greater than 0; any other input causes the prompt to repeat.
Both helpers call cin.clear() and cin.ignore() to flush the input stream before retrying, preventing an infinite loop on bad input.

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Relationship to the Web Version

The C++ source uses the same monthly compounding formula as the JavaScript version. The key difference is that the C++ calculateWithMonthlyDeposit() adds the deposit before applying interest each month, while the JavaScript version applies interest first then adds the deposit. The final balance figures differ slightly as a result. Both models demonstrate the educational concept of compound growth.

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