Which concept in structured programming allows the reuse of code in C?

The concept in structured programming that allows the reuse of code in C is called "Functions". Functions are reusable pieces of code that perform a specific task. They can be defined once and used multiple times in a program, allowing for code reuse.

Here are the steps to create and use functions in C:

1. Function Declaration: Before you can use a function, it must be declared. The declaration includes the function name, return type, and parameters. For example: int add(int a, int b);

2. Function Definition: After declaration, the function must be defined. The definition includes the actual code that will be executed when the function is called. For example:

int add(int a, int b) {
    return a + b;
}

3. Function Call: Once the function is declared and defined, it can be called from anywhere in the program. To call a function, you use its name and provide values for its parameters. For example: int sum = add(5, 7);

By using functions, you can write a piece of code once and then reuse it whenever you need it, which makes your programs shorter, easier to read, and easier to maintain.

The concept in structured programming that allows the reuse of code in C is called "Functions".

Here are the steps to explain how it works:

1. Definition: A function is a group of statements that together perform a task. In C programming, a function is a way of packaging code that does a particular job into a named chunk.

2. Reusability: Once a function is defined, it can be used over and over and over again. You can invoke the same function many times in your program, which saves you the work of having to write the same code again.

3. Structure: A function in C has a name, can have parameters, and has a body (which contains the code). The general form of a function definition in C programming language is as follows:

return_type function_name( parameter list )
{
   body of the function
}

4. Calling a Function: When a program calls a function, the program control is transferred to the called function. A called function performs a defined task and when its return statement is executed or when its function-ending closing brace is reached, it returns the program control back to the main program.

5. Example: Here is a simple example of a function in C that calculates the sum of two integers:

#include <stdio.h>

// function definition
int sum(int a, int b) {
   return a + b;
}

int main() {
   // function call
   printf("Sum is: %d", sum(10, 20));
   return 0;
}

In this example, the function sum is defined to take two parameters and return their sum. This function can be called from anywhere in the code, allowing for reusability of the code that calculates the sum of two numbers.