Question

What will this print if the user types 3.1526 ? float x; cin >> x; cout << setprecision(2) << x << endl << fixed << x;

A. 3.2 3.15
B. 3.15 3.15
C. 3.15 3.1526
D. 3.20 3.15

Answer 1

When a user inputs 3.1526, the program prints '3.2' first due to the setprecision(2) without fixed, which rounds to one decimal place. Then '3.15' after fixed is applied, ensuring two decimal places. The correct answer is 'A. 3.2 3.15'.

Step-by-step explanation:

The code provided prompts the user to type a floating-point number, which in this case is 3.1526. The output will be affected by the setprecision manipulator from the iostream library and the fixed manipulator:

• After cin >> x, the variable x holds the value 3.1526.
• When cout << setprecision(2) << x is executed, only two significant figures will be printed out. However, without the fixed manipulator beforehand, setprecision(2) may lead to scientific notation or truncation of the fractional part, which is not desired here.
• The first output will be 3.2 because setprecision rounds the number to one decimal place in the absence of fixed.
• Adding fixed before the variable x when printed the second time forces the output to have exactly two decimal places. Hence, 3.15 is printed.

Therefore, the correct answer is A. 3.2 3.15.