How to Round a Decimal Number in C++ Using Stream Manipulator?

How can we round a decimal number in C++ using stream manipulator?

Based on the following variable definition and stream manipulator setting:

Given the following variable definition double exam = 1.2345678; What is the output based on the stream manipulator setting shown below?

cout << setprecision(); cout << exam << endl;

a. 1.2346 b. 1.235 c. 1.2346 d. 1.23

Answer:

The setprecision() function is called without a specified precision. Therefore, the variable 'exam' will be output with the default precision, 6 digits after the decimal point, so the value printed will be 1.234568 (since it's automatically rounded).

In C++, you can round a decimal number using the stream manipulator function setprecision(). When setprecision() is called without specifying a precision, it will output the default precision, which is typically 6 digits after the decimal point.

In the given code snippet, a double variable named 'exam' is defined with a value of 1.2345678. The setprecision() function is then called without any input, meaning it will not alter the precision of the output. As a result, the output will be the default precision of 6 digits after the decimal point, rounding the value to 1.234568.

It's important to note that specifying a precision value in setprecision() can change the rounding behavior of the output. In this case, since no precision is specified, the default behavior is to round to 6 digits after the decimal point.

Understanding how stream manipulators like setprecision() work in C++ can help you control the formatting and rounding of decimal numbers in your programs.

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