Functions / Methods in Programming Languages - Quiz

Let's analyze the given expression and the output of the Java Math functions:

Expression:

Math.pow(36, 0.5) + Math.cbrt(125) + Math.ceil(4.2) + Math.floor(7.9)
        

Explanation:

1. Math.pow(36, 0.5):

   The Math.pow(x, y) method returns x raised to the power of y.
   Math.pow(36, 0.5) calculates the square root of 36.
   √36 = 6.0

2. Math.cbrt(125):

   The Math.cbrt(x) method returns the cube root of x.
   Math.cbrt(125) calculates the cube root of 125.
   ∛125 = 5.0

3. Math.ceil(4.2):

   The Math.ceil(x) method returns the smallest integer greater than or equal to x.
   Math.ceil(4.2) returns the smallest integer greater than or equal to 4.2.
   Math.ceil(4.2) = 5.0

4. Math.floor(7.9):

   The Math.floor(x) method returns the largest integer less than or equal to x.
   Math.floor(7.9) returns the largest integer less than or equal to 7.9.
   Math.floor(7.9) = 7.0

Calculating the Sum:

Adding these values together:
6.0 + 5.0 + 5.0 + 7.0 = 23.0

Conclusion:

The output of the expression is: 23.0

Let's analyze the given Java code step by step to predict its output:

Code:

String str1 = "great";
String str2 = "minds";

System.out.println(str1.substring(0, 2).concat(str2.substring(1)));
System.out.println("WH" + (str1.substring(2).toUpperCase()));
        

Explanation:

1. First Line:

   System.out.println(str1.substring(0, 2).concat(str2.substring(1)));\
   - str1.substring(0, 2) extracts a substring from str1 starting at index 0 up to, but not including, index 2.
   For str1 = "great", str1.substring(0, 2) results in "gr".
   - str2.substring(1) extracts a substring from str2 starting at index 1 to the end of the string.
   For str2 = "minds", str2.substring(1) results in "inds".
   - Concatenating these results:
   "gr".concat("inds") results in "grinds".
   - Therefore, the first println statement prints "grinds".

2. Second Line:

   System.out.println("WH" + (str1.substring(2).toUpperCase()));
   - str1.substring(2) extracts a substring from str1 starting at index 2 to the end of the string.
   For str1 = "great", str1.substring(2) results in "eat".
   - str1.substring(2).toUpperCase() converts this substring to uppercase.
   "eat".toUpperCase() results in "EAT".
   - Concatenating "WH" with the result:
   "WH" + "EAT" results in "WHEAT".
   - Therefore, the second println statement prints "WHEAT".

Conclusion:

The output of the code is:

• grinds
• WHEAT

The parseLong() function is a member of the Long wrapper class.

Explanation:

• parseLong() is a static method provided by the Long wrapper class in Java.
• It is used to convert a String into a long value.

Correct Answer:

a) Long wrapper class

Math.random()

Explanation:

• Double.parseDouble() converts the string values "26.0" and "74.0" into double values.
• Adding 26.0 and 74.0 results in 100.0.

Explanation:

In Call by Value, the values of the actual parameters are copied to the formal parameters. Any changes made to the formal parameters do not affect the actual parameters.

nextLine()

Reason — nextLine() reads the input till the end of line so it can read a full sentence including spaces.

char check (int x)

Reason — The prototype of a function is written in the given syntax:

return_type method_name(arguments)

Thus, the method has the prototype given below:

char check (int x)

Pure method

Reason — A method which does not modify the value of variables is termed as a pure method.