An algorithm is a defined and ordered set of instructions or steps used to solve a computational problem or perform mathematical calculations in a program.

Algorithms are written in the form of code or pseudocode so that they can be converted into computer programs. The steps in the algorithm must be clear and unambiguous, sequential, and produce the desired solution or output.

The quality of an algorithm is judged by its speed, accuracy of results, efficiency of memory usage, and ease of implementation and understanding. Algorithms are categorized according to their functions such as sorting, searching, optimization, data compression, graphical programming, cryptography, and others.