COBOL

A business data-processing language from 1959, still in production in banking, insurance, and government.

27 steps across 1 tours, from the basics to complete programs.

The tours

First released: 1960
Created by: The CODASYL committee, on Grace Hopper's foundations
Typing: Static; every field described to the digit by its PICTURE clause
Snippets target: COBOL 2023
File extensions: .cob, .cbl, .cpy

What it is for

COBOL runs the back offices of the world: card networks, bank cores, insurance claims, payroll, and government benefit systems, mostly on IBM mainframes that process billions of transactions a day. Estimates of the installed base run to hundreds of billions of lines, and the point is not that it is old — it is that it keeps working, decade after decade, under audit.

The language was designed for business data, and it shows. A PICTURE clause describes every field to the digit — 9(5)V99 is five digits, an invisible decimal point, and two more — so money arithmetic is exact by construction, not by library. The verbs read like office memos: MOVE, ADD, INSPECT, PERFORM. Managers were supposed to be able to read it; fifty years later, maintenance programmers are glad they can.

Modern COBOL is livelier than its reputation. Free format retired the punch-card columns, GnuCOBOL (which checks every seed here) compiles it to C on anything, and the 2002-and-later standards added intrinsic functions, Unicode, and object features. When several US states hit the news in 2020 begging for COBOL programmers, the joke wrote itself — but so did the job listings.

Where it came from

In 1959 a Pentagon-convened committee — CODASYL — set out to build one business language for every computer, drawing heavily on Grace Hopper's FLOW-MATIC, the first English-like data processing language. COBOL-60 was published the next year, and in December 1960 the same program ran on an RCA machine and a Univac: the first real demonstration that source code could outlive its hardware.

Standards in 1968, 1974, and 1985 carried COBOL through the era when it was simply what business computing meant; by some 1970s estimates it was the most widely used language on Earth. Y2K made its invisible empire briefly visible, as armies of programmers patched two-digit years in systems nobody had touched in decades — and found them otherwise sound.

COBOL 2002 brought free format and object orientation, and the standard still updates — COBOL 2023 is current. OpenCOBOL appeared in 2002 and matured into GnuCOBOL, a free compiler that translates COBOL to C; it is the compiler behind every seed in this tour. The mainframes have not gone anywhere, and neither has the language.

What it is like to type

COBOL types like prose in uppercase: long hyphenated names (WORKING-STORAGE, TIDE-FEET), spelled-out verbs, and a period closing every sentence. There are almost no symbol clusters — the densest thing you will meet is a PICTURE string like $$$,$$9.99 — so the rhythm is steady words, not punctuation bursts. Because the words run long, tokens come slower here than in any other language at the same finger speed; the three-star bars are set lower to match, not to flatter.

Practice COBOL