BitBench

digital logic is something every CS student encounters, but running through truth tables by hand is slow and error-prone. BitBench is a terminal-based Java program that simulates the core building blocks of digital electronics adders, subtractors, and flip-flops using raw bit manipulation, no libraries, no overhead.

you type in binary inputs, it gives you the exact outputs a real circuit would produce.

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what it simulates

combinational circuits

• Half Adder — SUM and CARRY from two single bits
• Full Adder — SUM and CARRY with a carry-in
• Half Subtractor — DIFF and BORROW from two bits
• Full Subtractor — DIFF and BORROW with a borrow-in

sequential circuits (flip-flops)

• SR Flip-Flop — Set/Reset latch with invalid state handling
• JK Flip-Flop — eliminates the undefined SR state via toggle
• T Flip-Flop — toggles output on T=1
• D Flip-Flop — output simply follows input

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how it actually works

all logic is implemented using Java's bitwise operators — ^ (XOR), & (AND), ~ (NOT), | (OR). no if (a + b) shortcuts. the gates are the operators.

for example, a half adder in the code looks like:

sum   = a ^ b
carry = a & b

flip-flops iterate over both possible current states (Q=0 and Q=1) for each input pair, so you see the full state transition table, not just one scenario.

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quickstart

no cloning needed. just download and run:

1. download BitBench.jar v1.0 from Releases
2. open terminal in your download folder
3. run:

java -jar BitBench.jar

requirements

Java

• Java Runtime Environment (JRE) 8 or above
• check if you have it: java -version
• if not, download from https://adoptium.net — one-time install

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run it

Java

option 1 — releases (easiest, no cloning)

download BitBench.jar v1.0 from Releases, then:

java -jar BitBench.jar

option 2 — build from source

git clone https://github.com/utkarsh094/BitBench.git
cd BitBench
javac src/java/BitBench.java
java -cp src/java BitBench

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on Windows:

gcc src/c/BitBench.c -o BitBench.exe
BitBench.exe

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usage

once running, you'll see a menu:

===== DIGITAL CIRCUIT PROGRAM =====
1. Half Adder
2. Full Adder
3. Half Subtractor
4. Full Subtractor
5. SR Flip-Flop
6. JK Flip-Flop
7. T Flip-Flop
8. D Flip-Flop
9. Exit

pick a circuit, enter binary strings as input (e.g. 0110), and it prints a formatted truth table for each bit pair.

example — Half Adder

Enter A: 011
Enter B: 101

A B | SUM CARRY
----------------
0 1 |  1   0
1 0 |  1   0
1 1 |  0   1

inputs must be the same length. the program tells you if they aren't.

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repo structure

BitBench/
├── src/
│   └── java/
│       └── BitBench.java
├── bin/
│   └── BitBench.jar
├── .gitignore
├── LICENSE
└── README.md

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limitations

• inputs are validated for equal length but not for non-binary characters entering anything other than 0 and 1 will give wrong output silently
• SR Flip-Flop skips the S=1, R=1 state (invalid/undefined), as is standard
• no graphical output — this is purely terminal

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license

MIT — see LICENSE