A wide variety of computer programming languages exist to carry out tasks at various levels, but they all run on the concepts of command sequences, conditional operations and looping instructions. The command sequence is the list of operations for the program to perform, such as listing character strings and printing them. Conditional operations tell the program how to treat data based on whether it satisfies preset parameters, like numbers exceeding a set value. Looping tasks execute repeatedly.
One of the most well-known conditional operations is the "if-then-else" statement. The "if" part of the instruction provides the comparison for data. The "then" provides subsequent instruction, such as printing or adding to a database. The "else" section dictates what to do with data that does not fit parameters.
Another important concept in programming is data types. Several data types exist, including numeric, character and logical. Numeric data includes both fractions and integers. String data includes text that cannot be used in mathematical calculations and is usually enclosed in quotation marks in the program.
Older programming languages like BASIC require instructions be typed directly, interfacing with the hardware of the computer. Programming has become more sophisticated and makes use of compilers. These are user-friendly software programs that take the instructions and translate them into programming language.