Software Engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software...
, a loop counter is the term often used to refer to the variable
Variable (programming)
In computer programming, a variable is a symbolic name given to some known or unknown quantity or information, for the purpose of allowing the name to be used independently of the information it represents...
In computer science a for loop is a programming language statement which allows code to be repeatedly executed. A for loop is classified as an iteration statement....
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
construct). It is so named because most uses of this construct result in the variable taking on a range of integer values in some orderly sequence (e.g., starting at 0 and end at 10 in increments of 1)
Iteration means the act of repeating a process usually with the aim of approaching a desired goal or target or result. Each repetition of the process is also called an "iteration," and the results of one iteration are used as the starting point for the next iteration.-Mathematics:Iteration in...
of a loop, providing a unique value for each individual iteration. The loop counter is used to decide when the loop should terminate and for program flow to continue to the next instruction after the loop.
A common identifier naming convention is for the loop counter to use the variable names i, j and k (and so on if needed), where i would be the most outer loop, j the next inner loop, etc. The reverse order is also used by some programmers. This style is generally agreed to have originated from the early programming of FORTRAN
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
, where these variable names beginning with these letters were implicitly declared as having an integer type, and so were obvious choices for loop counters that were only temporarily required. The practice also dates back further to mathematical notation
Mathematical notation
Mathematical notation is a system of symbolic representations of mathematical objects and ideas. Mathematical notations are used in mathematics, the physical sciences, engineering, and economics...
Index notation is used in mathematics and computer programming to specify the elements of matrices or the components of a vector. The formalism of how indices are used varies according to the discipline...
SUM can refer to:* The State University of Management* Soccer United Marketing* Society for the Establishment of Useful Manufactures* StartUp-Manager* Software User’s Manual,as from DOD-STD-2 167A, and MIL-STD-498...
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
In computer science a for loop is a programming language statement which allows code to be repeatedly executed. A for loop is classified as an iteration statement....
