Before we study about computer programming, we should understand about what algorithm is. Here is a short explanation about algorithm copied from whatis.techtarget.com and wikipedia.org.

An algorithm (pronounced AL-go-rith-um) is a procedure or formula for solving a problem. The word derives from the name of the mathematician, Mohammed ibn-Musa al-Khwarizmi, who was part of the royal court in Baghdad and who lived from about 780 to 850. Al-Khwarizmi's work is the likely source for the word algebra as well.

A computer program can be viewed as an elaborate algorithm. In mathematics and computer science, an algorithm usually means a small procedure that solves a recurrent problem.

In mathematics, computing, linguistics and related subjects, an algorithm is a sequence of finite instructions, often used for calculation and data processing. It is formally a type of effective method in which a list of well-defined instructions for completing a task will, when given an initial state, proceed through a well-defined series of successive states, eventually terminating in an end-state. The transition from one state to the next is not necessarily deterministic; some algorithms, known as probabilistic algorithms, incorporate randomness.

the following is the more formal coding of the algorithm in pseudocode or pidgin code:

Algorithm LargestNumber
    Input: A non-empty list of numbers L.
    Output: The largest number in the list L.
      largest ← L0
       for each item in the list L≥1, do
          if the item > largest, then 
           largest ← the item
       return largest