C Functions: Declaration & Calling Guide

In the C language, the declaration and calling of functions are as follows:

1. Function declaration:
   The syntax format of a function declaration is:

return_type function_name(parameters);

return_type represents the return type of the function, function_name represents the name of the function, and parameters represents the list of parameters of the function.

For example, here is an example of a function declaration:

int add(int a, int b);

1. Function invocation:
   The syntax format for function invocation is:

return_value = function_name(arguments);

return_value represents the return value of the function, function_name represents the name of the function, and arguments represents the list of parameters of the function.

For example, here is an example of a function call:

int result = add(3, 4);

When calling a function, make sure the function is declared before the call, otherwise the compiler will throw an error. Additionally, the function’s parameter list and return type must match the declaration, or else it will also result in a compilation error.