Learn BCPL with Real Code Examples

BCPL is a precursor to C and emphasizes simplicity, portability, and efficiency for systems programming.

It uses a single, typeless word type, relying on programmer discipline rather than type enforcement.

It introduced concepts such as strings, arrays, and pointers in a portable, low-level context.

Single word data type (typeless)

Procedures and global variables

Strings and arrays implemented as word sequences

Flexible memory manipulation

Conditional and loop control structures

Words as the fundamental data unit

Global and local variables

Procedures for modularization

Arrays and strings

Conditional and loop control structures

Source/ - BCPL source files

Lib/ - runtime and helper libraries

Bin/ - compiled executables

Docs/ - documentation and notes

Tests/ - test programs and examples

Write source files with .b extension

Define global variables and procedures

Use arrays and strings for data storage

Compile modules using BCPL compiler

Link compiled code and run program

Beginner: writing simple word-based programs

Intermediate: implementing basic algorithms

Advanced: creating compilers or OS prototypes

Expert: systems programming and low-level memory management

Historical study: analyzing early programming language design

Predecessor to C with typeless words

Simpler than Pascal or Modula-2

Excellent for compiler and OS development

Lacks type safety of modern languages

Influential but mostly historical today

1966 – BCPL created by Martin Richards

Late 1960s – Used for early compiler development

1970s – Ported to multiple hardware platforms

1980s – Influence seen in C language

2025 – Primarily studied for historical and academic purposes

Word: the fundamental typeless unit of data

Procedure: reusable code block

Array: sequence of words

String: array of characters stored as words

Global variable: accessible across procedures