Question

What will each of the following program segments display? for (int count \(=1 ; \text { count } < =10 ; \text { count }++)\) $\\{\text { cout } < < ++\text { count } < < " \quad " ; \quad$ // This is a bad thing to do! \\}

Short answer

Answer: The output of the program segment will be: 2 4 6 8 10

Step-by-step solution

Understand the Variables

In this program segment, we have one integer variable 'count'. It is initially set to 1.

Analyze the Loop

The given loop is a 'for' loop, and it has the following structure: - Initialization: 'count' is set to 1. - Condition: The loop will continue as long as 'count' is less than or equal to 10. - Update: 'count' is incremented by 1 after each iteration (++count).

Analyze the Output Statement

Inside the loop, there is a 'cout' statement that outputs the value of the 'count' variable, followed by a space. However, there is an important thing to notice: the 'count' variable is incremented again (++count) inside the output statement. This means that 'count' will be incremented twice in each iteration.

Understand the Issue in the Code

The code has a comment indicating that incrementing 'count' in the output statement is a 'bad thing to do'. It's because modifying the loop counter variable inside the loop body can lead to unexpected results, make the code harder to understand and maintain.

Predict the Output

Now, let's analyze each iteration: - Iteration 1: count = 1 (initial value), output (++count) = 2, update (count++) making count = 3 - Iteration 2: count = 3, output (++count) = 4, update (count++) making count = 5 - Iteration 3: count = 5, output (++count) = 6, update (count++) making count = 7 - Iteration 4: count = 7, output (++count) = 8, update (count++) making count = 9 - Iteration 5: count = 9, output (++count) = 10, update (count++) making count = 11 The loop will terminate after the 5th iteration as the condition 'count <= 10' will no longer be true ('count'=11). So, the final output of this program segment will be: 2 4 6 8 10