FOP tutorial 6 (methods) by Amjad Alsharafi

q1

2019-11-01 01:21:48 UTC

public class q1 {

public static void main(String[] args) {

for (int i = 1; i <= 20; i++) {

int s = generateTriangularNumber(i);
System.out.println(s);
}
}

static int generateTriangularNumber(int n) {
int sum = 0;

for (int i = 1; i <= n; i++) {
sum += i;
}
return sum;
}

}

1c

jiayi0819 — 2019-11-01 01:22:37 UTC

public static void function(int n, int k){
int up=1;
int down=1;
for(int i=((n-k)+1); i<=n; i++){
up *= i;
}
for(int i=1; i<=k; i++){
down *= i;
}
System.out.println(up/down);
}

q2

2019-11-01 01:42:02 UTC

public class q2 {

public static void main(String[] args) {
int row = 8;

System.out.println("Triangle");
for (int i = 1; i <= row; i++) {
multiPrint(row - i, ' ');
multiPrint(2 * i - 1, '*');
System.out.println();
}

System.out.println("\n\nDiamond");
for (int i = 1; i <= row; i++) {
multiPrint(row - i, ' ');
multiPrint(2 * i - 1, '*');
System.out.println();
}

for (int i = row -1; i >= 0; i--) {
multiPrint(row - i, ' ');
multiPrint(2 * i - 1, '*');
System.out.println();
}

}

static void multiPrint(int n, char c) {
// 1
for (int i = 0; i < n; i++) {
System.out.print(c);
}

// 2
/* String s = "";
for (int i = 0; i < n; i++) {
s += c;
}
System.out.print(s); */
}

}

q3

2019-11-01 01:59:07 UTC

import java.util.Arrays;

public class q3 {

public static void main(String[] args) {
int arr[] = {1234, 5647, 4342, 3412};
System.out.println(Arrays.toString(arr));
reverseDigits(arr);
System.out.println(Arrays.toString(arr));

}

/**
* pass by reference method
*/
static void reverseDigits(int[] arr) {
int b, c;
for (int i = 0; i < arr.length; i++) {
b = arr[i];
c = 0;

while (b != 0) {
c *= 10; // shift to left
c += b % 10; // add the lst digit of b
b /= 10; // shift to right
}

arr[i] = c;
}
}

}

q4

2019-11-01 02:02:41 UTC

public class q4 {
public static void main(String[] args) {
// test
System.out.println("GCD of 24 and 8 is " + gcd(24, 8));
}

static int gcd(int a, int b) {
while(b != 0) {
int t = b;
b = a % b;
a = t;
}
return a;
}
}

q5

2019-11-01 02:08:12 UTC

import java.util.Random;
import java.util.Scanner;

public class q5 {

public static void main(String[] args) {
Random r = new Random();
Scanner sc = new Scanner(System.in);

int a = r.nextInt(13);
int b = r.nextInt(13);
System.out.printf("%d x %d = ", a, b);
int ans = sc.nextInt();

if(checkEqual(a, b, ans)) {
System.out.println("CORRECT");
}
else
{
System.out.println("WRONG");
}



}

static boolean checkEqual(int a, int b, int ans) {
// 1
/* if(a * b == ans)
return true;
else
return false; */

// 2
return a * b == ans;
}
}

q6

2019-11-01 02:26:34 UTC

public class q6 {

public static void main(String[] args) {
int N = 20;

System.out.println("Palidromic Primes(20)");
for (int i = 0, j = 1; i < N; j++) {
if (isPalindromicPrime(j)) {
System.out.println(j);
i++;
}
}
System.out.println("EPrimes(20)");

for (int i = 0, j = 1; i < N; j++) {
if (isEprime(j)) {
System.out.println(j);
i++;
}
}
}

static boolean isPrime(int n) {
if (n == 2) {
return true;
} else if (n > 2 && n % 2 == 0) {
return false;
} else {
for (int i = 3; i < n / 2; i++) {
if (n % i == 0) {
return false;
}
}
}

return true;
}

static int reverseInt(int b) {
int c = 0;

while (b != 0) {
c *= 10; // shift to left
c += b % 10; // add the lst digit of b
b /= 10; // shift to right
}

return c;
}

static boolean isPalindrome(int a) {
return a == reverseInt(a);
}

static boolean isPalindromicPrime(int a) {
return isPrime(a) && isPalindrome(a);
}

static boolean isEprime(int a) {
return isPrime(a) && isPrime(reverseInt(a)) && !isPalindrome(a);
}
}

2019-11-01 02:42:19 UTC

Random r = new Random(); Scanner sc = new Scanner(System.in); int a = r.nextInt(13); int b = r.nextInt(13); System.out.printf("%d x %d = ", a, b); int ans = sc.nextInt(); if(checkEqual(a, b, ans)) { System.out.println("CORRECT"); } else { System.out.println("WRONG"); } } static boolean checkEqual(int a, int b, int ans) { // 1 /* if(a * b == ans) return true; else return false; */ // 2 return a * b == ans; }

2019-11-01 02:43:25 UTC

public class q1 { public static void main(String[] args) { for (int i = 1; i <= 20; i++) { int s = generateTriangularNumber(i); System.out.println(s); } } static int generateTriangularNumber(int n) { int sum = 0; for (int i = 1; i <= n; i++) { sum += i; } return sum; } }

2019-11-01 02:51:47 UTC

int b, c; for (int i = 0; i < arr.length; i++) { b = arr[i]; c = 0; while (b != 0) { c *= 10; // shift to left c += b % 10; // add the lst digit of b b /= 10; // shift to right } arr[i] = c; }