Almost all the programming languages uses functions. Functions are the entities which are grouping a set of statements which do a specific job or set of jobs.
Example: sum of integers, sum of float number, complex number addition.
All the above three can be implemented as a single function or three separate functions.
When someone wants to use that, a function can be simply called.
So function implementation happens as
- Function prototype or Function declaration
- Function definition or function implementation
- Function call
- It is necessary to specify the name of the function, the parameters and the return type to the compiler that the function is being defined in this program.
- The prototype ends with a semicolon
int sum(int, int); //function prototype
This is the actual function definition which shows the function implementation.
for the above syntax here is the function
int sum(int a, int b)
The above function is returning an integer, hence int is specified. If a function is not returning any thing, a void can be used.
The last is the function call, which when being needed a simple call will make the function to work. Here is the example
z=sum(x,y); //function call
printf(“The sum is %d”, z);
Once the function is called, the control goes to the actual implementation and execute the statements inside the function and the value is returned to the main function.
Components of a function
- Name of the function
- Return type
- Parameters or arguments
In the above example
name of the function is : sum()
return type is : int
parameters are: int, int