Solved 2020 Practical Paper ISC Computer Science — Question 1
Back to all questionsQuestion 1
A Prime-Adam integer is a positive integer (without leading zeros) which is a prime as well as an Adam number.
Prime number: A number which has only two factors, i.e. 1 and the number itself.
Example: 2, 3, 5, 7 ... etc.
Adam number: The square of a number and the square of its reverse are reverse to each other.
Example: If n = 13 and reverse of 'n' = 31, then,
(13)2 = 169
(31)2 = 961 which is reverse of 169
thus 13, is an Adam number.
Accept two positive integers m and n, where m is less than n as user input. Display all Prime-Adam integers that are in the range between m and n (both inclusive) and output them along with the frequency, in the format given below:
Test your program with the following data and some random data:
Example 1
INPUT:
m = 5
n = 100
OUTPUT:
THE PRIME-ADAM INTEGERS ARE:
11 13 31
FREQUENCY OF PRIME-ADAM INTEGERS IS: 3
Example 2
INPUT:
m = 100
n = 200
OUTPUT:
THE PRIME-ADAM INTEGERS ARE:
101 103 113
FREQUENCY OF PRIME-ADAM INTEGERS IS: 3
Example 3
INPUT:
m = 50
n = 70
OUTPUT:
THE PRIME-ADAM INTEGERS ARE:
NIL
FREQUENCY OF PRIME-ADAM INTEGERS IS: 0
Example 4
INPUT:
m = 700
n = 450
OUTPUT:
INVALID INPUT
Solution
import java.util.Scanner;
public class PrimeAdam
{
public static int reverse(int num) {
int rev = 0;
while (num != 0) {
int d = num % 10;
rev = rev * 10 + d;
num /= 10;
}
return rev;
}
public static boolean isAdam(int num) {
int sqNum = num * num;
int revNum = reverse(num);
int sqRevNum = revNum * revNum;
int rev = reverse(sqNum);
return rev == sqRevNum;
}
public static boolean isPrime(int num) {
int c = 0;
for (int i = 1; i <= num; i++) {
if (num % i == 0) {
c++;
}
}
return c == 2;
}
public static void main(String args[]) {
Scanner in = new Scanner(System.in);
System.out.print("Enter the value of m: ");
int m = in.nextInt();
System.out.print("Enter the value of n: ");
int n = in.nextInt();
int count = 0;
if (m >= n) {
System.out.println("INVALID INPUT");
return;
}
System.out.println("THE PRIME-ADAM INTEGERS ARE:");
for (int i = m; i <= n; i++) {
boolean adam = isAdam(i);
if (adam) {
boolean prime = isPrime(i);
if (prime) {
System.out.print(i + " ");
count++;
}
}
}
if (count == 0) {
System.out.print("NIL");
}
System.out.println();
System.out.println("FREQUENCY OF PRIME-ADAM INTEGERS IS: " + count);
}
}Output
import
java.util.Scanner
;
public
class
PrimeAdam
{
public
static
int
reverse
(
int
num
) {
int
rev
=
0
;
while
(num
!=
0
) {
int
d
=
num
%
10
;
rev
=
rev
*
10
+
d;
num
/=
10
;
}
return
rev;
}
public
static
boolean
isAdam
(
int
num
) {
int
sqNum
=
num
*
num;
int
revNum
=
reverse(num);
int
sqRevNum
=
revNum
*
revNum;
int
rev
=
reverse(sqNum);
return
rev
==
sqRevNum;
}
public
static
boolean
isPrime
(
int
num
) {
int
c
=
0
;
for
(
int
i
=
1
; i
<=
num; i
++
) {
if
(num
%
i
==
0
) {
c
++
;
}
}
return
c
==
2
;
}
public
static
void
main
(
String
args
[]) {
Scanner
in
=
new
Scanner
(
System
.
in);
System
.
out
.
print(
"
Enter the value of m:
"
);
int
m
=
in
.
nextInt();
System
.
out
.
print(
"
Enter the value of n:
"
);
int
n
=
in
.
nextInt();
int
count
=
0
;
if
(m
>=
n) {
System
.
out
.
println(
"
INVALID INPUT
"
);
return
;
}
System
.
out
.
println(
"
THE PRIME-ADAM INTEGERS ARE:
"
);
for
(
int
i
=
m; i
<=
n; i
++
) {
boolean
adam
=
isAdam(i);
if
(adam) {
boolean
prime
=
isPrime(i);
if
(prime) {
System
.
out
.
print(i
+
"
"
);
count
++
;
}
}
}
if
(count
==
0
) {
System
.
out
.
print(
"
NIL
"
);
}
System
.
out
.
println();
System
.
out
.
println(
"
FREQUENCY OF PRIME-ADAM INTEGERS IS:
"
+
count);
}
}
Output