A computer program is a list of instructions that tell a computer what to do. Everything a computer does is done by using a computer program. A computer program is written in a programming language. Programs stored in the memory of a computer enable the computer to perform tasks in sequence or even intermittently. The idea of an internally stored program was introduced in the late 1940s by the Hungarian-born mathematician John von Neumann. The first digital computer designed with internal programming capacity was the EDVAC (an acronym for Electronic Discrete Variable Automatic Computer), constructed in 1949.
Some examples of computer programs:
A computer program is stored as a file on the computer's hard drive. When the user runs the program, the file is read by the computer, and the processor reads the data in the file as a list of instructions. Then the computer does what the program tells it to do.
A computer program is written by a programmer. It is very difficult to write in the ones and zeroes of machine code, which is what the computer can read, so computer programmers write in a programming language, such as BASIC, C, or Java. Once it is written, the programmer uses a compiler to turn it into a language that the computer can understand.
There are also bad programs, called malware, written by people who want to do bad things to a computer. Some are spyware, trying to steal information from the computer. Some try to damage the data stored on the hard drive. Some others send users to web sites that offer to sell them things. Some are computer viruses or ransomware.