Download Sample Java Exam

Question 1 a) Write a method find which puts the numbers that are divisible by
5 in a given two-dimensional array into a one-dimensional array and returns this
array. The method will put -1 after the last element in the one-dimensional array.
public static int[] find(int[][]mat){
int []ar=new int[15];
int i=0;
for (int r=0;r<mat.length; r++)
for (int c=0; c<mat[0].length; c++)
if (mat[r][c]%5==0)
{
ar[i]=mat[r][c];
i++;
}
ar[i]=-1;
return(ar);
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1
}
b) Write a main method to:
 Input a two-dimensional array ar1 having 10x15 elements.
 Call the above method to create a one-dimensional array ar2.
 Display the contents of the second array until -1 is reached.
import java.util.Scanner;
public class q1 {
static Scanner kb=new Scanner(System.in);
public static void main(String[] args){
int[][] ar1=new int[3][5];
int[] ar2=new int[150];
int r,c,i;
for (r=0;r<ar1.length; r++)
{
System.out.println("Enter " + ar1[0].length + " integers:
");
for (c=0; c<ar1[0].length; c++)
ar1[r][c]=kb.nextInt();
}
ar2=find(ar1);
System.out.println("Numbers in the array divisible by 5 ");
i=0;
while (ar2[i]!=-1)
{
System.out.println(ar2[i]);
i++;
}
}
Question 2 Trace the program segments and show the output in the boxes.
2.00
4.00
3.00
9.00
4.00
16.00
i = 5 k =
11
2
public class tr3{
public static void main(String args[]) {
int i=2,k;
do
{
for(k=3; k<11; k+=4)
System.out.printf("%5.2f\n", Math.pow(i,k/3));
}
while(i++ < 4);
System.out.println("i = " + i + " k = " + k);
}
}
Page
a. (8 pts)
b. (7 pts)
public class tr1{
public static void main(String args[]){
int i=1;
***3
&&&4
***7
&&&8
***11
12
while (i < 10)
switch(i%4)
{
case 1:
i+=2;
System.out.println("*** " + i);
case 2:
i++;
break;
case 3:
i+=3;
default:
System.out.println("&&& " + i++);
}
System.out.println(i);
}
}
c. (5 pts)
public class tr2{
public static void main(String args[]) {
int[]a={3,5,1,6,9,4};
int i;
***3
???0
???2
***9
---4
for (i=0;i<6;i=i+2)
{
if (a[i] >= i)
System.out.println("*** " + a[i]);
if (a[i] >= a[i+1])
System.out.println("--- " + a[i+1]);
else
System.out.println("??? " + i);
}
}
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}
Question 3 Given the following methods:
public static int m1( int[] a) {
int tot = 0;
for( int i = a.length – 1; i >= 0; i--)
if( i % 2 == 1 || a[i] > 0)
tot += a[i];
return tot;
}
public static boolean m2( double d) {
return (int) d == (int)(d * 100) % 100;
}
public static int m3( int n) {
int ret = 0;
while( n != 0){
ret = ret + n % 10;
n = n / 10;
}
return ret;
}
What is the output of the following method calls:
a)
int[] ar1 = {3, 4, 1, 0, -3, -8, 1, 6, 7};
a: 14
System.out.println( "a: " + m1( ar1));
b)
int[] ar2 = {13, -4, 1, 10, -3, +8};
System.out.println( "b: " + m3( m1( ar2)));
c)
if( m2(34.43))
b: 10
c: 16
System.out.println( "c: " + m3( 123));
else
System.out.println( "c: " + m3( 358));
d: false
4
System.out.println( "d: " + m2( m3( 358)));
Page
d)
Question 4 Write a complete Java program to input an integer N from the keyboard
and print N lines with random numbers between 10 – 99. It will print N random
numbers in the first line and decrease by one each printed line as shown below:
Sample outputs:
Start you code here and continue at the back of the paper:
import java.util.*;
public class CS111Mt2Q4 {
public static void main( String[] args){
Scanner kb = new Scanner( System.in);
int N,r;
System.out.print( "Enter an integer: ");
N= kb.nextInt();
for( int i = 0; i < N; i++){
for( int j = N - i; j > 0; j--){
r = (int)(Math.random()*89 + 10);
System.out.print( r + " ");
}
System.out.println();
}
}
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}