sccash/README.md

sccash - Simple C Cash

A lightweight, fast CLI currency converter written in C for USD, JPY, and EUR conversions.

Features

• Dual Mode Operation: Command-line arguments for scripting, interactive prompts for manual use
• Table Formatted Output: Clean, readable conversion results
• Lightweight: No external dependencies, standard C library only
• Fast: Compiles to a small, efficient binary
• Error Handling: Clear error messages for invalid inputs

Exchange Rates (as of March 26, 2026)

• 1 USD = 159.67 JPY
• 1 USD = 0.866 EUR
• 1 EUR = 184.20 JPY

Note: These rates are hardcoded and may not reflect current market rates.

Compilation

gcc -o sccash sccash.c -Wall -O2

Or for a static binary:

gcc -o sccash sccash.c -Wall -O2 -static

Installation

Option 1: Local Installation

# Compile first
gcc -o sccash sccash.c -Wall -O2

# Copy to local bin directory
mkdir -p ~/bin
cp sccash ~/bin/

# Add to PATH if not already
export PATH="$HOME/bin:$PATH"

Option 2: System-wide Installation

# Compile first
gcc -o sccash sccash.c -Wall -O2

# Install to system path (requires sudo)
sudo cp sccash /usr/local/bin/

# Verify installation
sccash --help

Usage

CLI Mode

Pass three arguments: amount, from_currency, and to_currency.

./sccash <amount> <from> <to>

Examples:

# Convert 100 USD to JPY
./sccash 100 USD JPY

# Convert 50 EUR to USD
./sccash 50 EUR USD

# Convert 1000 JPY to EUR
./sccash 1000 JPY EUR

Interactive Mode

Run without arguments for interactive prompts:

./sccash

Example session:

=== sccash - Simple C Cash ===

Available currencies: USD, JPY, EUR

Enter amount: 100
Convert from (USD/JPY/EUR): USD
Convert to (USD/JPY/EUR): JPY

+--------+---------------+--------+----------------+
|  FROM  |    AMOUNT     |   TO   |  CONVERTED     |
+--------+---------------+--------+----------------+
| USD    |        100.00 | JPY    |       15967.00 |
+--------+---------------+--------+----------------+

Show all conversions? (y/n): y

+--------+---------------+--------+----------------+
|  FROM  |    AMOUNT     |   TO   |  CONVERTED     |
+--------+---------------+--------+----------------+
| USD    |        100.00 | JPY    |       15967.00 |
| USD    |        100.00 | EUR    |          86.60 |
+--------+---------------+--------+----------------+

Exchange Rates (as of March 26, 2026):
  1 USD = 159.67 JPY
  1 USD = 0.866 EUR
  1 EUR = 184.20 JPY

Sample Output

$ ./sccash 250 USD EUR

+--------+---------------+--------+----------------+
|  FROM  |    AMOUNT     |   TO   |  CONVERTED     |
+--------+---------------+--------+----------------+
| USD    |        250.00 | EUR    |         216.50 |
+--------+---------------+--------+----------------+

Error Handling

$ ./sccash 100 GBP USD
Error: Invalid source currency 'GBP'
Available: USD, JPY, EUR

$ ./sccash
=== sccash - Simple C Cash ===

Available currencies: USD, JPY, EUR

Enter amount: invalid
Error: Invalid amount

Architecture

sccash uses USD as the base currency for all conversions:

1. Convert source amount to USD
2. Convert USD amount to target currency

This approach minimizes rounding errors and keeps the code simple and maintainable.

Currencies Supported

• USD - United States Dollar
• JPY - Japanese Yen
• EUR - Euro

Currency codes are case-insensitive (usd, USD, Usd all work).

Technical Details

• Lines of Code: ~200
• Dependencies: Standard C library only (stdio.h, stdlib.h, string.h, ctype.h)
• Memory Usage: Minimal - uses only the stack
• Output Format: Fixed-width table with 2 decimal precision

Building for Different Platforms

Linux

gcc -o sccash sccash.c -Wall -O2

macOS

clang -o sccash sccash.c -Wall -O2

Windows (MinGW)

gcc -o sccash.exe sccash.c -Wall -O2

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

Contributing

This is a simple, focused tool. Contributions should maintain the design goals:

• Keep it lightweight
• No external dependencies
• Simple, readable code
• Clear error messages

Author

Created with simplicity and performance in mind.

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Note: Currency values fluctuate constantly. The exchange rates in this tool are fixed as of March 26, 2026. For real-time rates, consider using a service with API integration.