differenciate btw.-a)local & public variables b)pre-defined & user defined functions c)fnctn prototype,defination & fnctn code.use code examples.
Difference between local and public variables
public variables once declared they can be used any where in the program i.e. even in many functions while local variables are local to a functional and cant be used beyond that function.
Difference between pre-defined and user-defined function
The user-defined functions are defined by a user as per its own requirement while library functions or pre-defined come with compiler.