Dennis Ritchie, 70, a computer scientist who changed modern technology by writing an elegantly simple computer programming language, was found dead at his home in Murray Hill, N.J., his former colleague Rob Pike said.

Pike received word Oct. 12 that Dr. Ritchie’s body had been discovered last weekend. A cause of death was not immediately available.

As the news of his death spread throughout the computer science world, historians and computer enthusiasts compared the bearded, introverted Dr. Ritchie to media-savvy Apple co-founder Steve Jobs, who died Oct. 5.

“It’s sort of ‘apples’ and oranges,” said Paul Ceruzzi, a Smithsonian historian and expert on the history of computers. “Ritchie was under the radar. His name was not a household name at all, but . . . if you had a microscope and could look in a computer, you’d see his work everywhere inside.”

Dr. Ritchie worked at Bell Laboratories for four decades, from his time as a Harvard doctoral student until his retirement in 2007. He was the inventor of the programming language known as C and co-inventor of the operating system Unix, another innovation that came from Bell Labs in the late 1960s and early ’70s.

When Dr. Ritchie went to Bell, computer programming language was arcane and impenetrable for many computer gurus of the era. As a young scientist, Dr. Ritchie went to work on a language that was sophisticated yet simple. Something of a night owl, he often went to the office about noon and worked into the night from his home.

He named his creation C because programming language that came before it was called B.

“C is a terse, elegant, deceptively simple language that allows programmers almost unlimited flexibility,” technology writer Charles Petzold wrote in the New York Times in 1996. “It appeals to the macho instincts of young and wild PC hackers, as well to the puzzle-solving impulses of more mature programmers because of its power and the variety of ways to solve problems.”

C was not without flaws — it was vulnerable to viruses, Petzold wrote — but it soon became the most popular programming language. It allowed programmers to do in a few months jobs that with other languages would have taken a year or more.

C language was the foundation for Unix, the operating system Dr. Ritchie helped develop with Bell colleague Kenneth Thompson. Microsoft Windows-based personal computers and many Apple products run on its descendents. It is the ancestor of “most of the infrastructure of our wired society,” Ceruzzi said.

Dr. Ritchie and Thompson received the Turing Award from the Association for Computing Machinery in 1983 — an early recognition of what would be an enduring contribution to technology, said Tim Bergin, a computer language historian and professor emeritus at American University.

More honors followed. In 1998, President Bill Clinton awarded the two men the National Medal of Technology and Innovation “for their invention of UNIX operating system and the C programming language, which together have led to enormous growth of an entire industry, thereby enhancing American leadership in the Information Age.” Early this year, they received the prestigious Japan Prize for science and technology.

Dennis MacAlistair Ritchie was born Sept. 9, 1941, in Bronxville, N.Y., to a scientific family. His father, Alistair Ritchie, worked at Bell and co-wrote a book on switching circuits. The younger Ritchie attended Harvard, where he earned a bachelor’s degree in physics in 1963 and a doctorate in applied mathematics in 1968.

“My undergraduate experience convinced me that I was not smart enough to be a physicist, and that computers were quite neat,” he wrote in a biography for Bell Labs. “My graduate school experience convinced me that I was not smart enough to be an expert in the theory of algorithms and also that I liked procedural languages better than functional ones.”

Survivors include two brothers, William Ritchie of Alexandria and John Ritchie of Newton, Mass., and one sister, Lynn Ritchie of Hexham, England.

Dr. Ritchie co-wrote the book “The C Programming Language,” a volume on the order of a technological Oxford English Dictionary.

He had a lighter side, too. With Pike, he lined up the magician duo Penn and Teller for a practical joke on his boss, Nobel Prize-winning physicist Arno Penzias. In the stunt, videotaped in 1989 and available on YouTube, the two scientists convinced Penzias that they had invented fancy voice-recognition technology. “It took him days to recover,” the voice-over says.