Functions in programming are blocks of code designed to perform specific tasks.User-defined functions, on the other hand, allow programmers to create their own functions to perform specific tasks.There are two types of functions: predefined and user-defined.Predefined functions are built-in functions that are provided by the programming language or its standard library.Value-returning functions consist of a heading, which includes the function's name and other properties, such as the return type.They also have formal parameters, which are variables declared in the heading, and actual parameters, which are variables or expressions passed to the function during a function call.The syntax of a value-returning function includes the function's type, name, formal parameter list, and a block of statements.The formal parameter list specifies the data types and identifiers of the parameters.