What does scanner.nextDouble() do?

What does scanner.nextDouble() do?

• A. Reads a long value
• B. Reads a double value
• C. Reads a string
• D. Reads a float value

Answer: (B)

Understanding how input is parsed with a scanner is key here. Scanner.nextDouble() reads the next token from the input and converts it into a double-precision floating-point value, returning it as the primitive type double. It consumes that token so subsequent reads start after it. If the next token isn’t a valid double representation, an exception is raised. This method handles typical numeric formats like 3.14, -2.0, or even 6 (since integers are valid doubles). It does not read a long value (that would be nextLong), nor a string (that would be next), nor a float value (that would be nextFloat).

Understanding how input is parsed with a scanner is key here. Scanner.nextDouble() reads the next token from the input and converts it into a double-precision floating-point value, returning it as the primitive type double. It consumes that token so subsequent reads start after it. If the next token isn’t a valid double representation, an exception is raised. This method handles typical numeric formats like 3.14, -2.0, or even 6 (since integers are valid doubles). It does not read a long value (that would be nextLong), nor a string (that would be next), nor a float value (that would be nextFloat).