decrement

Decrement is the act or process of decreasing a quantity, usually by a fixed amount such as one unit. In mathematics, a decrement refers to subtracting a constant, often denoted n -> n - k, with k commonly equal to 1. The term is used in contexts such as iterative processes and recurrence relations where a variable is reduced stepwise.

In computer science, decrement is a common operation on integers. Many programming languages provide a decrement operator that reduces a value by one. In languages that differentiate prefix and postfix forms, such as C, C++, Java, and JavaScript, pre-decrement applies the subtraction before yielding a value, while post-decrement yields the original value and then performs the subtraction. This distinction matters for expressions with side effects and operator evaluation order. Decrement operations may cause underflow if the value is at its minimum representable value, especially for unsigned integers, in which case behavior is typically defined by the language (e.g., wraparound or a runtime error).

In algorithm design, decrementation is commonly used to progress toward a loop termination condition, for example in for or while loops that count downward.

In data analysis and statistics, a decrement can describe a reduction or decline in quantities such as inventory, population, or measured metrics over time.

Etymology: from Latin decrementum, from decrescere 'to decrease'. See also: increment, successor, underflow.