Question

Write a \(C++\) statement that prints the message "The number is valid." if the variable temperature is within the range -50 through 150

Short answer

Question: Write a C++ statement that checks if a variable temperature is within the range -50 to 150, and if it is, the program should print "The number is valid." Answer: ```cpp #include int main() { int temperature; std::cin >> temperature; if (temperature >= -50 && temperature <= 150) { std::cout << "The number is valid." << std::endl; } return 0; } ```

Step-by-step solution

Include necessary libraries

To use input/output operations in C++, we need to include the "iostream" library. This library contains functions like "cout" and "cin" that allow us to interact with the console. ```cpp #include ```

Check if the temperature is within the specific range

We can use an if statement to check if the temperature is within the range -50 through 150. In this case, we can use the logical AND (&&) operator to check two conditions at once. We want to check if the temperature is greater than or equal to -50 and less than or equal to 150. If these conditions are true, the temperature is within the range. ```cpp if (temperature >= -50 && temperature <= 150) { ```

Print the message if the condition is met

Inside the if statement, use "cout" (standard output stream) to print the message "The number is valid." followed by "endl" to end the line. ```cpp std::cout << "The number is valid." << std::endl; } ```

Complete Code

Here's the complete C++ statement that checks if the variable temperature is within the range -50 through 150, and prints the message accordingly. ```cpp #include int main() { int temperature; std::cin >> temperature; if (temperature >= -50 && temperature <= 150) { std::cout << "The number is valid." << std::endl; } return 0; } ```

Key concepts

C++ if statement

In C++, the if statement is a fundamental control-structure that allows a program to make decisions. It evaluates a condition, typically a comparison between two values, and directs the path of execution depending on whether the condition is true or false.

For instance, if you have a variable such as temperature in your program, you can use an if statement to perform actions based on the value of temperature. Here is a simple structure of an if statement:

if (condition) {    // block of code to be executed if the condition is true}

Improving your use of if statements involves understanding conditions and being able to predict the flow of execution in your program. One tip is to make sure that the conditions you test are valid and that you handle possible edge cases, like the limits of a range.

Logical AND operator

In C++, the Logical AND operator, denoted as &&, allows you to combine multiple conditions within your if statement. It serves as a gatekeeper for the controlled block of code: all conditions must be true for the contained statements to execute.

For example, you can use it to check if a number is within a range, like in this scenario:

if (temperature >= -50 && temperature <= 150) {    // this code will run if temperature is between -50 and 150}

The logical AND operator is useful in many situations, from validating user inputs to ensuring variables fall within a desired range. The crucial point is that every single condition connected by && must be met. If even one is false, the if statement will not execute its block of code.

C++ Range Checking

The technique of Range Checking within C++ involves verifying that a variable's value falls within a certain limit or range. This is particularly important for ensuring that values conform to expected bounds and can help in preventing errors or unexpected behavior in programs.

Checking a range in C++ often uses the if statement combined with the Logical AND operator:

if (variable >= lower_bound && variable <= upper_bound) {    // Code to execute if range conditions are met}

Remember to always check both the lower and upper limits of the range. Moreover, when improving your range checking practice, make sure the range you are testing is correct and that your variables are of the right data type to hold the values you expect them to.

iostream library

The iostream library in C++ is a core component used for performing input and output operations. It includes tools like cin (standard input stream) and cout (standard output stream) which allow your programs to interact with the user through the console

To use this library, you need to include it at the beginning of your code:

#include 

Utilizing the iostream library correctly can significantly improve user interaction. Remember that you can use cin to read input from the user, and cout to display messages back to the user. Always ensure you include this library when dealing with console input or output to avoid compilation errors.