The invention of the computer is a complex story that involves many contributors over several decades, rather than a single inventor or a specific year like 1940. However, the 1940s were a pivotal decade in the development of modern computers, as this period saw the creation of some of the first programmable electronic computers.

One of the most significant early computers developed in the 1940s was the ENIAC (Electronic Numerical Integrator and Computer), which is often considered the first general-purpose electronic digital computer. ENIAC was designed and built by John Presper Eckert and John William Mauchly at the University of Pennsylvania. It was completed in 1945 and publicly unveiled in 1946. ENIAC was a massive machine, weighing over 27 tons and occupying 1,800 square feet. It was capable of performing complex calculations at speeds far exceeding those of mechanical computers.

Another important computer from the 1940s was the Colossus, developed by British engineer Tommy Flowers during World War II. Colossus was used to break German military codes, particularly the Lorenz cipher, and played a crucial role in the Allied war effort. Unlike ENIAC, Colossus was not a general-purpose computer but was designed specifically for codebreaking.

In addition to these machines, Alan Turing, a British mathematician and computer scientist, made foundational contributions to computer science during this period. Turing's theoretical work on algorithms and computation, including the concept of the Turing machine, laid the groundwork for modern computing. Although Turing did not build a physical computer himself, his ideas were instrumental in the development of early computers.

The 1940s also saw the development of the Harvard Mark I, an electromechanical computer designed by Howard Aiken and built by IBM. Completed in 1944, the Mark I was one of the first large-scale automatic digital computers.

In summary, while no single person "invented the computer" in 1940, the decade was a critical period in the evolution of computing technology. Key figures like Eckert, Mauchly, Flowers, Turing, and Aiken, along with their teams, made groundbreaking contributions that led to the creation of the first electronic and programmable computers. These early machines set the stage for the rapid advancements in computing that followed in the latter half of the 20th century.