Is it possible to declare functions inside structure

You could define a function pointer inside a struct as follows:. You will have to assign the pointer to a specific function whenever you instantiate the struct. The idea is to put a pointer to a function inside the struct. The function is then declared outside of the struct. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Can I define a function inside a C structure?

Asked 9 years, 1 month ago. Active 10 months ago. Viewed k times. When the prototype occurs with the code NO semicolon is used. In C, the "main" function is treated the same as every function, it has a return type and in some cases accepts inputs via parameters.

The only difference is that the main function is "called" by the operating system when the user runs the program. Thus the main function is always the first code executed when a program starts. Every C function must specify the type of data that is being generated. For example, the max function above returns a value of type "double". Inside the function, the line "return X;" must be found, where X is a value or variable containing a value of the given type. When a line of code in a function that says: "return X;" is executed, the function "ends" and no more code in the function is executed.

The value of X or the value in the variable represented by X becomes the result of the function. When one piece of code invokes or calls a function, it is done by the following syntax:. The function name must match exactly the name of the function in the function prototype. The args are a list of values or variables containing values that are "passed" into the function.

The number of args "passed" into a function must exactly match the number of parameters required for the function. The type of each arg must exactly match the type of each parameter. The return variable type must exactly match the return type of the function. The "variable" in the example above must have a type equivalent to the return type of the function. Inside the function, somewhere will be the line "return X". The value of X is then copied into the "variable".

A Parameter is the symbolic name for "data" that goes into a function. Pass by Value, means that a copy of the data is made and stored by way of the name of the parameter. Any changes to the parameter have NO affect on data in the calling function. A reference parameter "refers" to the original data in the calling function. Arrays are always pass by reference in C. Because a struct declaration does not establish scope , nested types, enumerations and enumerators introduced by declarations within struct-declaration-list are visible in the surrounding scope where the struct is defined.

Create account Log in. Namespaces Page Discussion. Views View Edit History. From cppreference. Declarations pointer array enum. In other contexts, names the previously-declared struct, and attr-spec-seq is not allowed. Two bytes excess. Run this code. Atomic operations C Thread support C