Question

Write a function declaration and a function definition for a function that takes three arguments, all of type \(i n t,\) and that returns the sum of its three arguments.

Short answer

Answer: To declare and define a function that takes three integers and returns their sum, follow these steps: 1. Declare the function using the return type 'int', a name such as 'sumOfThree', and three integer input arguments: ```cpp int sumOfThree(int a, int b, int c); ``` 2. Define the function by repeating the declaration and adding a pair of curly braces '{ }' with instructions for computing the sum and returning it inside: ```cpp int sumOfThree(int a, int b, int c) { int sum = a + b + c; return sum; } ``` The function 'sumOfThree' is now complete and can be called with three integer arguments to find their sum.

Step-by-step solution

Declare the function

To declare the function, first determine the function's return type, which should be an integer since we are returning the sum of three integers. Next, choose a name for the function, for example, 'sumOfThree'. Then, specify the input arguments, which are three integers. Put all this information together to get the function declaration: ```cpp int sumOfThree(int a, int b, int c); ```

Define the function

Now that the function is declared, we need to define it to implement the sum operation. To do this, re-write the function declaration, and then add a pair of curly braces `{}` right after it. Inside the curly braces, write the instructions to compute the sum of the three input integers and return it. ```cpp int sumOfThree(int a, int b, int c) { int sum = a + b + c; return sum; } ``` The function is now complete, and it will successfully compute the sum of any three input integers when called with appropriate arguments.