What is the difference between read and write in computer programming?

Answer 1

A "Read" operation occurs when a computer program reads information from a computer file/table (e.g. to be displayed on a screen). The "read" operation gets information out of a file (some computer languages use the term "get" instead of "read"). After a "read", the information from the file/table is available to the computer program but none of the information that was read from the file/table is changed in any way.

A "Write" operation occurs when a computer program adds new information, or changes existing information in a computer file/table.

An example of a computer program adding new information to a file would be when a company adds a new hire's details into its employee master file.

An example of a computer program changing existing information would be when a company updates its employee master file if an existing employee changes their address. In this example, since the employee already existed in the employee file, the computer program would have had to perform a "read" at some point, to get the information out of the file/table (a fundamental rule of computer programming is that you can't update a record in a file/table unless you perform a "read" operation to get a hold of that record in the first place).

Either way, the "Write" operation is what puts information in to a file. Some computer languages use the terms "put" or "update", but these are both "write" operations in general IT terms.

Bottom line: Read = get information. Write = add or change information.

HTH