Computer Programming & Problem Solving - II

Functions in C are the basic building blocks of a C program. A function is a set of statements enclosed within curly brackets ({}) that take inputs, do the computation, and provide the resultant output. You can call a function multiple times, thereby allowing reusability and modularity in C programming. 

The pointer in C language is a variable which stores the address of another variable. This variable can be of type int, char, array, function, or any other pointer. The size of the pointer depends on the architecture. However, in 32-bit architecture the size of a pointer is 2 byte. 

Both Structure and Union in C are user-defined data types in C programming that hold multiple members of different data types. Structures are used when we need to store distinct values for all the members in a unique memory location while unions help manage memory efficiently. 

Searching here refers to finding an item in the array that meets some specified criterion. Sorting refers to rearranging all the items in the array into increasing or decreasing order (where the meaning of increasing and decreasing can depend on the context).