(TEST CORRECTIONS JAVA PROGRAMMING: WHY IS THIS THE CORRECT ANSWER AND WHAT IS THE CORRECT ANSWER FOR C-E)

a) Which of the following correctly gives random numbers between -10 and 10 inclusively? Note: Math.random() creates a random number of [0,1).

Selected Answer:

int n = (int)(Math.random() * 10)-20;

Correct Answer:

int n = (int)(Math.random() * 21)-10;

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b) How many times is the println statement executed? for (int i = 0; i < 7; i++) for (int j = 0; j < i; j++) System.out.println(i * j);

Selected Answer: 7

Corrected Answer: 21

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c) What is output? Convert the following loop into a for loop.

int sum = 10;

int i = 2;

while (i <= 6){

sum += 2 * i;

i++;

}

System.out.println(sum);

Your answer format: (no more than 6 lines)

Ouput: ________________

______________________ // Converted code

______________________

______________________

______________________

_______________________

Selected Answer:

for ( int i = 2; i < 7; i++)

for (int sum = 10; sum< i; sum += 2*i)

}

System.out.println(sum);

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d)

Write output produced by the following code.

for (int i = 1; i <= 5; i++) { for (int j = 6; j >= i; j--) System.out.print(" * "); System.out.println(" ! "); }

Selected Answer:

! * * * * * *

! * * * * *

! * * * *

! * * *

! * *

*

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e) Identify and correct the errors in the following method to computer the sum of two integers:

int sum (int a, int b); {

int result;

result = x + y;

}

Selected Answer:

int sum ( int a, int b) { int result; result = x + y; } public int method1( int x ) { if ( x <= 10 ) x += 1; else x -= 1; return x; }

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