‘An algorithm is a precisely-defined sequence of rules telling how to produce specified output information from given input information in a finite number of steps. A particular representation of an algorithm is called a program, just as we use the word “data” to stand for a particular representation of “information”.’
– Donald E. Knuth (1974, p. 323) [Computer Science and its Relation to Mathematics. The American Mathematical Monthly, 81(4), 323–343]