How did ALGOL influence later programming languages such as Pascal and C?

ALGOL was a highly influential computer programming language that established several foundational concepts for modern software development. Its influence on descendants like Pascal and C is primarily due to the following innovations:12

• Block Structure: ALGOL introduced the concept of organizing programs into blocks containing both data and instructions. This structure allowed for the construction of large programs from smaller, manageable components.13
• Recursive Procedures: It supported subprograms that could invoke themselves, a feature that became standard in many later languages.12
• Syntax Notation: ALGOL introduced Backus–Naur Form, a formal notation used to define the grammar of programming languages, which remains a standard tool in computer science.12
• Machine Independence: Unlike earlier languages such as FORTRAN, ALGOL was designed to be machine-independent, setting a precedent for portable code.2

While Pascal adopted ALGOL’s notation and emphasis on structure, it expanded upon these ideas by introducing user-defined data types to better organize complex information. C also emerged from this lineage, evolving into a powerful and flexible language that became the basis for the UNIX operating system.42