Question

Write a function definition for a function called in_order that takes three arguments of type int. The function returns true if the three arguments are in ascending order; otherwise, it returns false. For example, in_order (1,2,3) and in_order (1,2,2) both return true, while in_order (1,3,2) returns false.

Short answer

Answer: Yes. Explanation: In the given example, we have three numbers: 3, 5, and 7. By comparing the numbers, we can see that 3 is less than or equal to 5 and 5 is less than or equal to 7. Therefore, these numbers are in ascending order. When we call the 'in_order' function with these arguments, it will return True as follows: ```python result = in_order(3, 5, 7) print(result) # Output: True ```

Step-by-step solution

Define the function

First, let's define the function called 'in_order' with three input parameters, as follows: ```python def in_order(a, b, c): ```

Check if the numbers are in ascending order

Now, we need to check if the numbers are in ascending order. We will do this by using nested if statements. If 'a' is less than or equal to 'b' AND 'b' is less than or equal to 'c', then the numbers are in ascending order. Otherwise, they are not. Here is the code: ```python if a <= b: if b <= c: return True return False ```

Combine steps and finalize the function

Finally, let's combine the steps together and write the complete function definition: ```python def in_order(a, b, c): if a <= b: if b <= c: return True return False ``` Now, we have the 'in_order' function defined, which will return the expected results for the given examples.

Key concepts

Function Argument Types

Understanding function arguments is crucial for effective programming in C++. Function arguments, also known as parameters, are the variables that we pass to a function when we call it. In the exercise, the function in_order takes three arguments, all of which are of type int. In C++, there are mainly three types of function arguments: by value, by reference, and by pointer.

• By Value: This method copies the actual value of an argument into the formal parameter of the function. In the in_order function, the integers are passed by value, meaning any changes to these parameters within the function have no effect on the original arguments.
• By Reference: By using reference arguments (denoted with an ampersand &), a function can modify the actual value of the argument.
• By Pointer: Similar to references, arguments can be passed as pointers (denoted with an asterisk *), allowing the function to modify the actual value at the address being pointed to.

Choosing the correct argument type is important, as it impacts both functionality and efficiency. Passing by value is a safe choice when you need to ensure that the original variable remains unchanged. However, it may involve unnecessary data copying for large objects, leading to less efficient code.

Control Structures in C++

Control structures in C++, such as if statements and loops, are fundamental to directing the flow of a program. The exercise demonstrates the use of nested if statements, a type of control structure that allows for decision making in code.

• If Statements: An if statement will execute a block of code if its condition is true. In the function in_order, the condition checks whether the first argument is less than or equal to the second.
• Nested If Statements: When an if statement is placed within another if statement, it is known as a nested if. In the provided solution, if the first argument is indeed less than or equal to the second, a second if statement checks if the second argument is less than or equal to the third.
• Other Control Structures: While if statements are used in the in_order function, C++ also provides other control structures such as for and while loops for iterating over data, and switch-case statements for multi-branch decisions.

Understanding these structures is essential for creating programs that can respond to different conditions and perform various tasks.The nested if statements could also be consolidated into a single if condition using the logical AND operator &&, thus optimizing the control flow.

Boolean Return Values

In many programming scenarios, it's necessary to return a simple yes or no answer from a function. In C++ terminology, this is done by returning a boolean value, either true or false. The in_order function exemplifies this well; it returns true if the arguments are in ascending order, and false otherwise.

• Boolean Type: In C++, boolean is a data type that can hold one of two values: true or false. Functions that perform checks or need to indicate the success or failure of an operation typically return a boolean value.
• Return Statement: The return statement ends function execution and specifies the value that should be returned to the caller. In the in_order function, the return value immediately conveys the result of the order check.

The use of boolean return values makes code easier to understand and maintain, as it provides a straightforward method of communicating binary outcomes.