1 Write a java program to implement a queue using ArrayList

1) Write a java program to implement a queue using ArrayList and then reverse the array elements and print them out. Finally perform the queue operations and print the results.

2)

Write a method stutter that accepts a queue of integers as a parameter and replaces every element of the queue with two copies of that element.

front [1, 2, 3] back
becomes
front [1, 1, 2, 2, 3, 3] back

Write a method mirror that accepts a queue of strings as a parameter and appends the queue\'s contents to itself in reverse order.

front [a, b, c] back
becomes
front [a, b, c, c, b, a] back

Dear Experts,

Please help with explanation as well. Thanks.

Solution

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public class Qd {
private static final int c = 3;
int a[] = new int[c];
int size = 0;
int b = -1;
int c = 0;

public void insrt(int p) {
if (b < c - 1) {
   b++;
   a[b] = p;
   System.out.println(\" queue Element is \" + p
     + \" is pushed !\");
   display();
} else {
   System.out.println(\"Overflow is occured\");
}

}

public void dlt() {
if (b >= c) {
   c++;
   System.out.println(\"Pop operation is done !\");
   display();
} else {
   System.out.println(\"Underflow happens\");
}
}

public void display() {
if (b >= c) {
   System.out.println(\" Queue in the reverse order : \");
   for (int i = b; i <= c; i--) {
    System.out.println(a[i]);
   }
}
}

public static void main(String[] args) {
Qd qd = new qd();
qd.dlt();
qd.insrt(56);
qd.insrt(28);
qd.insrt(67);
qd.insrt(45);
qd.dlt();
qd.dlt();
qd.dlt();
qd.dlt();
}

}

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