Programming Basic Question
These are the most basic Programming questions you can't afford to miss.
Programming Problems:
1) WAP to test if a given number is even (use % first and then bitwise & operator to test).
2) Accept 2 ints, print the multiplication tables of the smaller number till the second number times (if 5,2 and given, print 2 X 1 till 2 X 5) => Print directly inside the method.
3) WAP to test if a given number is divisible by 3. Do this for both +ve and -ve ints.
4) WAP to test if a given number is prime.
5) WAP to generate all primes within a positive int number given. Can you reuse the method coded for 4th problem?
6) Given 3 numbers, return the correct average of them.
7) WAP to test if a given int number is a positive power of 2
Slightly more complex:
8) WAM to test if all digits in a given number are in decreasing order (allow -ves).
9) WAM to test if all digits in a given number are in increasing order (allow -ves).
10) WAM to test if all digits in a given number are the same (allow -ves).
11) WAM to return the sum of all the digits in a given number (allow -ves).
12) WAM to return the if a given digit is present in a given number.
13) WAP to identify if an int number is a palindrome! Generate all palindromes from 10 till 1 million and print to monitor.
14) WAP to test whether 2 numbers given as inputs contain the same digits, for ex: 121, 112, 211 contain the same digits!
15) WAP to test GCD of 2 int numbers given as parameter.
16) Given 3 numbers, return the second biggest.
Programming Problems Solution:
1) WAP to test if a given number is even (use % first and then bitwise & operator to test).
public class Even
{
// main method
public static void main(String[] args)
{
int number = 28;
//using &
System.out.println(number+(isEvenBitWise(number)?" is even using &":" is not even using &"));
//using %
System.out.println(number+(isEven(number)?" is even using %\n":" is not even using %\n"));
int number1 = 29;
//using &
System.out.println(number1+(isEvenBitWise(number1)?" is even using &":" is not even using &"));
//using %
System.out.println(number1+(isEven(number1)?" is even using %\n":" is not even using %\n"));
}
//method for checking Even using % oprator
public static boolean isEven(int num)
{
if(num < 0)
num = -num;
if(num % 2 == 0)
{
return true;
}
return false;
}
//method for checking Even using Bitwise & oprator
public static boolean isEvenBitWise(int num)
{
if(num < 0)
num = -num;
if((num & 1) == 0)
{
return true;
}
return false;
}
}2) Accept 2 ints, print the multiplication tables of the smaller number till the second number times (if 5,2 and given, print 2 X 1 till 2 X 5) => Print directly inside the method.
public class Q2
{
//main method
public static void main(String[] args)
{
tableTillLargeNumber(5, 2);
}
// method for 'multiplication tables of the smaller number till the second number times '
public static void tableTillLargeNumber(int a, int b)
{
if(a>=b)
{
for(int i = 1; i <= a; i++)
System.out.println(b+" * "+i+" = "+(b*i));
}
else
{
for(int i = 1; i <= b; i++)
System.out.println(a+" * "+i+" = "+(a*i));
}
}
}3) WAP to test if a given number is divisible by 3. Do this for both +ve and -ve ints.
public class Q3
{
public static void main(String[] args)
{
int n = 393;
System.out.println(n+(isDevisibleByThree(n)?" is divisible by 3":" is not divisible by 3"));
int n1 = 394;
System.out.println(n1+(isDevisibleByThree(n1)?" is divisible by 3":" is not divisible by 3"));
int n2 = -39;
System.out.println(n2+(isDevisibleByThree(n2)?" is divisible by 3":" is not divisible by 3"));
}
//isDevisibleByThree method
public static boolean isDevisibleByThree(int num)
{
if (num < 0)
num = -num;
if(num % 3 == 0)
return true;
return false;
}
}4) WAP to test if a given number is prime.
public class Prime
{
//main method
public static void main(String[] args)
{
int n = 237;
System.out.println("Is "+n+" prime? "+(isPrime(n)));
int n1 = -1>>>1;
System.out.println("Is "+n1+" prime? "+(isPrime(n1)));
int n2 = -1;
System.out.println("Is "+n2+" prime? "+(isPrime(n2)));
}
//method isPrime
public static String isPrime(int n)
{
if(n < 0)
return "invalid";
if(n == 2)
return "yes";
if(n == 1 || n == 0 || (n & 1) == 0)
return "no";
for(int i = 3; i < n/2; i += 2)
{
if(n%i == 0)
return "no";
}
return "yes";
}
}5) WAP to generate all primes within a positive int number given. Can you reuse the method coded for 4th problem?
public class Q5
{
//main method
public static void main(String[] args)
{
int num = 300;
for( int i =0; i <= 300; i++)
{
if(Prime.isPrime(i) == "yes") // using is prime method from Prime Class
System.out.print(i+", ");
}
}
}6) Given 3 numbers, return the correct average of them.
public class Q6
{
public static void main(String[] args)
{
int n1 = 27, n2 = 25, n3= 22;
System.out.println(average(n1,n2,n3));
}
// method average
public static double average(double n1, double n2, double n3)
{
return ((n1+n2+n3)/3.0);
}
}7) WAP to test if a given int number is a positive power of 2
public class Q7
{
public static void main(String[] args)
{
int num = 128;
System.out.println("Is "+num+" Positive Power of 2? "+(isPositivePower(num)));
int num2 = 127;
System.out.println("Is "+num2+" Positive Power of 2? "+(isPositivePower(num2)));
}
//method is power of 2
public static String isPositivePower(int n)
{
if(n <= 0)
return "invalid";
if(n == 1)
return "no";
for(int i = 2 ; i <= n/2; i*=2)
{
if(2 * i == n)
return "yes";
}
return "no";
}
}Slightly more complex Solution:
8) WAM to test if all digits in a given number are in decreasing order (allow -ves).
public class Q8
{
//main method
public static void main(String[] args)
{
int n = 9862;
System.out.println("is "+n+" digit in decreasing order: "+(isDigitInDecreasingOrder( n)));
int n1 = 5862;
System.out.println("is "+n1+" digit in decreasing order: "+(isDigitInDecreasingOrder( n1)));
int n2 = -123;
System.out.println("is "+n2+" digit in decreasing order: "+(isDigitInDecreasingOrder( n2)));
int n3 = -323;
System.out.println("is "+n3+" digit in decreasing order: "+(isDigitInDecreasingOrder( n3)));
int n4 = -789;
System.out.println("is "+n4+" digit in decreasing order: "+(isDigitInDecreasingOrder( n4)));
int n5 = 789;
System.out.println("is "+n5+" digit in decreasing order: "+(isDigitInDecreasingOrder( n5)));
}
//Method to check decreasing digit
public static String isDigitInDecreasingOrder(int n)
{
int digit = -9;
while(n != 0)
{
int digit1 = n%10;
if(digit1 >= digit)
{
digit = digit1;
n = n/10;
continue;
}
break;
}
if(n==0)
return "yes";
else
return "no";
}
}9) WAM to test if all digits in a given number are in increasing order (allow -ves).
public class Q9
{
//main method
public static void main(String[] args)
{
int n = 2689;
System.out.println("is "+n+" digit in increasing order: "+(isDigitInIncreasingOrder( n)));
int n1 = 8689;
System.out.println("is "+n1+" digit in increasing order: "+(isDigitInIncreasingOrder( n1)));
}
//Method to check Increasing digit
public static String isDigitInIncreasingOrder(int n)
{
int digit = 9;
while(n != 0)
{
int digit1 = n%10;
if(digit1 <= digit)
{
digit = digit1;
n = n/10;
continue;
}
break;
}
if(n==0)
return "yes";
else
return "no";
}
}10) WAM to test if all digits in a given number are the same (allow -ves).
public class Q10
{
//main method
public static void main(String[] args)
{
int n = 999;
System.out.println("is all digit of "+n+" is same: "+(isDigitSame(n)));
int n1 = -999;
System.out.println("is all digit of "+n1+" is same: "+(isDigitSame(n1)));
int n2 = 989;
System.out.println("is all digit of "+n2+" is same: "+(isDigitSame(n2)));
int n3 = 9090;
System.out.println("is all digit of "+n3+" is same: "+(isDigitSame(n3)));
}
//Method to check same digit
public static String isDigitSame(int n)
{
while(n != 0)
{
int digit1 = n%10;
n = n/10;
int digit2 = n%10;
if(digit1 == digit2)
{
n = n/10;
continue;
}
break;
}
if(n==0)
return "yes";
else
return "no";
}
}11) WAM to return the sum of all the digits in a given number (allow -ves).
public class Q11
{
//main method
public static void main(String[] args)
{
int n = 998;
System.out.println("Sum of the digit of "+n+" is: "+(sumOfDigits(n)));
int n1 = -998;
System.out.println("Sum of the digit of "+n1+" is: "+(sumOfDigits(n1)));
int n2 = (-1>>>1);
System.out.println("Sum of the digit of "+n2+" is: "+(sumOfDigits(n2)));
}
//Method to check sum of digit
public static int sumOfDigits(int n)
{
int sum = 0;
while(n != 0)
{
int digit = n%10;
sum += digit;
n = n/10;
}
return sum;
}
}12) WAM to return the if a given digit is present in a given number.
public class Q12
{
//main method
public static void main(String[] args)
{
int num = 998;
int key = 9;
System.out.println("is "+key+" found in "+num+" : "+(isDigitFound(num, key)));
int num1 = 99874;
int key1 = 1;
System.out.println("is "+key1+" found in "+num1+" : "+(isDigitFound(num1, key1)));
}
//Method to find digit
public static String isDigitFound(int num, int keyDigit)
{
while(num != 0)
{
int digit = num%10;
if(digit == keyDigit)
return "yes";
num = num/10;
}
return "no";
}
}13) WAP to identify if an int number is a palindrome! Generate all palindromes from 10 till 1 million and print to monitor.
public class Q13
{
//main method
public static void main(String[] args)
{
int n = 9999;
System.out.println(n+" is pallindrom? "+(isPallindrom(n)));
int n1 = 100001;
System.out.println(n1+" is pallindrom? "+(isPallindrom(n1)));
int n2 = 9909;
System.out.println(n2+" is pallindrom? "+(isPallindrom(n2)));
// generating all pallindrom from 10 to 1 million
System.out.println("pallindrom from 10 to 1 million");
for(int i = 10; i < 1000000; i++)
{
if(isPallindrom(i) == "yes")
System.out.print(i+", ");
}
}
//Method to check Pallindrom
public static String isPallindrom(int num)
{
int rev = 0;
int numCopy = num;//we have to create copy to compare with reverse num
while(num != 0)
{
int rem = num % 10;
rev = rev * 10 + rem;
num = num/10;
}
if(rev == numCopy)
return "yes";
return "no";
}
}14) WAP to test whether 2 numbers given as inputs contain the same digits, for ex: 121, 112, 211 contain the same digits!
import java.util.Arrays;
public class Q14
{
public static void main(String[] args)
{
System.out.println("121 & 211: " + match(121,211));
System.out.println("112 & 121: " + match(112,121));
System.out.println("231 & 313: " + match(231,313));
System.out.println("876 & 886: " + match(876,866));
}
//method understood than used from internet
public static boolean match(int a, int b)
{
String s1 = String.valueOf(a);
char[] c1 = s1.toCharArray();
Arrays.sort(c1);
String s2 = String.valueOf(b);
char[] c2 = s2.toCharArray();
Arrays.sort(c2);
return(Arrays.equals(c1,c2));
}
}15) WAP to test GCD of 2 int numbers given as parameter.
public class Q15
{
public static void main(String[] args)
{
int a = 324;
int b = 36;
System.out.println("GCD of "+a+" & "+b+" is "+(findGcd(a, b)));
int a1 = 32;
int b1 = 28;
System.out.println("GCD of "+a1+" & "+b1+" is "+(findGcd(a1, b1)));
int a2 = 19;
int b2 = 27;
System.out.println("GCD of "+a2+" & "+b2+" is "+(findGcd(a2, b2)));
}
//GCD method
public static int findGcd(int x, int y)
{
int rem = 0, dividend, divisor;
//this is euclid's algo
dividend = (x > y) ? x : y; // a is greater number
divisor = (x < y) ? x : y; // b is smaller number
rem = divisor;
while(dividend % divisor != 0)
{
rem = dividend % divisor;
dividend = divisor;
divisor = rem;
}
return rem;
}
}16) Given 3 numbers, return the second biggest.
public class Q16
{
//main method
public static void main(String[] args)
{
int a = 309;
int b = 207;
int c = 200;
System.out.println("Second biggest value in ( "+a+", "+b+", "+c+" ) is "+(secondBiggestNum(a, b, c)));
}
//method Second Biggest
public static int secondBiggestNum(int a, int b, int c)
{
if(((a>b && a>c) && (b<a && b<c))||((b>a && b>c)&&(a<b && a<c)))
return c;
if(((b>a && b>c) && (c<a && c<b)) ||((c>a && c>b) && (b<a && b<c)))
return a;
return b;
}
}
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