Code - Blocks I

Simple Programs PART-1 :

Easy understandable codes are without sample input & output, so please understand the basic logic's and work it out. some codes are given with sample input and output. Next-level to basic programs are available in 
PART-II module.

1) Java Program to Check if a Given Integer is Positive or Negative. 

import java.util.*;
public class Hello
{
    public static void main(String[] args) 
    {
        int n;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the number you want to check:");
        n = s.nextInt();
        if(n > 0)
        {
            System.out.println("Positive");
        }
        else if(n < 0)
        {
            System.out.println("Negative");
        }
        else
        {
            System.out.println("neither Positive nor Negative ");
        }
    }
}

2) Java Program to Check if a Given Integer is Odd or Even. 

import java.util.*;
public class Hello 
{
    public static void main(String[] args) 
    {
        int n;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the number you want to check:");
        n = s.nextInt();
        if(n % 2 == 0)
        {
            System.out.println("Even ");
        }
        else
        {
            System.out.println("Odd ");
  }
    }
}
3) Java Program to Find the Biggest of 3 Numbers.

import java.util.*;
public class Hello 
{
    public static void main(String[] args) 
    {
        int x, y, z;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the first number:");
        x = s.nextInt();
        System.out.print("Enter the second number:");
        y = s.nextInt();
        System.out.print("Enter the third number:");
        z = s.nextInt();
        if(x > y && x > z)
        {
            System.out.println("Largest number is:"+x);
        }
        else if(y > z)
        {
            System.out.println("Largest number is:"+y);
        }
        else
        {
            System.out.println("Largest number is:"+z);
        }
    }
}

4) Java Program to Calculate the Sum of Odd & Even Numbers. 

import java.util.*;
public class Hello 
{
    public static void main(String[] args) 
    {
        int n, sumEven = 0, sumOdd = 0;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the number of elements in array:");
        n = s.nextInt();
        int[] a = new int[n];          //to declare an array
        System.out.println("Enter the elements of the array:");
        for(int i = 0; i < n; i++)
        {
            a[i] = s.nextInt();
        }
        for(int i = 0; i < n; i++)
        {
            if(a[i] % 2 == 0)
            {
                sumEven = sumEven + a[i];
            }
            else
            {
                sumOdd = sumOdd + a[i];
            }
        }
        System.out.println("Sum of Even Numbers:"+sumEven);
        System.out.println("Sum of Odd Numbers:"+sumOdd);
    }
}
5) Java Program to Read Two Integers M and N & Swap their Values.
import java.util.*;
public class Swap_Integers 
{
    public static void main(String args[])
    {
        int m, n, temp;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the first number:");
        m = s.nextInt();
        System.out.print("Enter the second number:");
        n = s.nextInt();
        temp = m;
        m = n;
        n = temp;
        System.out.println("After Swapping");
        System.out.println("First number:"+m);
        System.out.println("Second number:"+n);
    }
}
6) Java Program to Reverse a Given Number. 
import java.util.*;
public class Reverse_Number 
{
    public static void main(String args[])
    {
        int m, n, sum = 0;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the number:");
        m = s.nextInt();
        System.out.println("Reverse of the number is:");
        while(m != 0)
        {
            n = m % 10;
            System.out.println(n);
            m = m / 10;
        }  
    }
}
7) Java Program to Accept two Integers and Check if they are Equal.

import java.util.*;
public class Equal_Integer 
{
    public static void main(String[] args) 
    {
        int m, n;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the first number:");
        m = s.nextInt();
        System.out.print("Enter the second number:");
        n = s.nextInt();
        if(m == n)
        {
            System.out.println(m+" and "+n+" are equal ");
        }
        else      
        {
           System.out.println(m+" and "+n+" are not equal ");
        }
    }
}
8)  Java Program to Compute the Sum of Digits in a given Integer.
import java.util.*;
public class Digit_Sum 
{
    public static void main(String args[])
    {
        int m, n, sum = 0;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the number:");
        m = s.nextInt();
        while(m > 0)
        {
            n = m % 10;
            sum = sum + n;
            m = m / 10;
        }
        System.out.println("Sum of Digits:"+sum);
    }
}
9) Java Program to Extract Digits at that position from a Given Integer
import java.util.*;
public class Extract_Digits 
{
    public static void main(String args[])
    {
        int n, m, a, i = 1, counter = 0;
        Scanner s=new Scanner(System.in);
        System.out.print("Enter any number:");
        n = s.nextInt();
        m = n;
        while(n > 0)
        {            n = n / 10;
            counter++;
        }
        while(m > 0)
        {
            a = m % 10;           
             System.out.println("Digits at position "+counter+":"+a);
            m = m / 10;
            counter--;
        }
    }
}
10 )  Java Program to Print Binary Equivalent of an Integer using Recursion. 

import java.util.*;
public class Binary_Recursion 
{
    public static void main(String[] args) 
    {
        int n;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the number:");
        n = s.nextInt();
        Binary_Recursion obj = new Binary_Recursion();
        String m = obj.Binary(n);
        System.out.println("Answer:"+m);
    }
    String Binary(int x)
    {
        if(x > 0)
        {
            int a = x % 2;
            x = x / 2;
            return a + "" + Binary(x);
        }
        return "";
    }
}

Sample input:
Enter the number:19

Sample output:
Answer:11001
11) Java Program to Increment by 1 All the Digits of a given Integer 

import java.util.*;
public class Increment_Digits
{
   public static void main(String[] args) 
   {
        int n, m = 0, a;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter any number:");
        n = s.nextInt();
        while(n > 0)
        {
            a = n % 10;
            a++;
            m = m * 10 + a;
            n = n / 10;
        }
        n = m;
        m = 0;
        while(n > 0)
        {
            a = n % 10;
            m = m * 10 + a;
            n = n / 10;
        }
        System.out.println("Result:"+m);
    }
}

Sample input:
Enter any number:4567

Sample output:
Result:5678
12) Java Program to Convert Integer Values into Binary. 

import java.util.*;
public class Decimal_Binary 
{    public static void main(String[] args) 
    {
        int n, m;
        String x = "";
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the Decimal Number:");
        n = s.nextInt();
        while(n > 0)
        {
            int a = n % 2;
            x = a + x;
            n = n / 2;
        }
        System.out.println(x);
    }
}

Sample input:
Enter the Decimal Number:19

Sample Output:
10011
13) Java Program to Convert a Given Number of Days in terms of Years, Weeks & Days. 

import java.util.*;
public class Year_Week_Day 
{
    public static void main(String args[])
    {
        int m, year, week, day;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter the number of days:");
        m = s.nextInt();
        year = m / 365;
        m = m % 365;
        System.out.println("No. of years:"+year);
        week = m / 7;
        m = m % 7;
        System.out.println("No. of weeks:"+week);
        day = m;
        System.out.println("No. of days:"+day);
    }
}

Sample input:
Enter the number of days:756

Sample output:
No. of years:2
No. of weeks:3
No. of days:5
14) Java Program to Convert Integer Values into Byte, Character, Float. 

import java.util.*;
public class Integer_Conversion
{
   public static void main(String[] args) 
    {
        int a;
        byte b;
        char c;
        float d;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter any integer:");
        a = s.nextInt();
        b = (byte) a;  
        System.out.println("Conversion into byte:"+b);
        c = (char) a;
        System.out.println("Conversion into char:"+c);
        d = a;
        System.out.println("Conversion into float:"+d);
    }
}
15) Java Program to Check if a Given Character is Vowel or Consonant using buffer reader function

import java.io.*;
import java.util.*;
public class Vowel_Consonant 
{
    public static void main(String[] args)
    {
        char n;
   BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter the character you want to check:");
        n = (char) bf.read();
        n=n.toLowerCase();
        if(n=='a'||n=='e'||n=='i'||n=='o'||n=='u')
        {
            System.out.print("Vowel");
        }
        else
        {
            System.out.ptint("Consonant");
        }
    }
}
16) Java Program to Check if given Alphabets are Uppercase or Lowercase or Digits. 

import java.io.*;
public class Alphabet_Check 
{
    public static void main(String args[])
    {
        char m;
    BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter any alphabet:");
        m = (char) bf.read();
        if(m >= 97 && m <= 123)
        {
            System.out.println("Lower Case");
        }
        else if(m >= 65 && m <= 96)
        {
            System.out.println("Upper Case");
        }
        else if(m >= 48 && m <= 57)
        {
            System.out.println("Digit");
        }
    }
}
17) Java Program to Find Largest Between Three Numbers Using Ternary Operator. 

import java.util.*;
public class Largest_Ternary 
{
    public static void main(String[] args) 
    {
        int a, b, c, d;
        Scanner s = new Scanner(System.in);
        System.out.println("Enter all three numbers:");
        a = s.nextInt();
        b = s.nextInt();
        c = s.nextInt();
        d = c > (a > b ? a : b) ? c : ((a > b) ? a : b);
        System.out.println("Largest Number:"+d);
    }
}
18) Java Program to Display Numbers from 1 to 10 Using For Loop. 

import java.util.*;
public class Use_For_Loop
{
    public static void main(String[] args)
    {
        for(int i = 1; i <= 10; i++)
        {
            System.out.println(i);
        }
    }
}
19) Java Program to Check Whether Given Number is Divisible by 5. 

import java.util.*;
public class Check_Divisiblity
{
    public static void main(String[] args) 
    {
        int n;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter any number:");
        n = s.nextInt();
        if(n % 5 == 0)
        {
            System.out.println(n+" is divisible by 5");
        }
        else
        {
            System.out.println(n+" is not divisible by 5");
        }
    }
}

20 ) Java Program to Print Multiplication Table for any Number. 


import java.util.*;
public class Multiplication_Table 
{
    public static void main(String[] args) 
    {
        Scanner s = new Scanner(System.in);
  System.out.print("Enter number:");        
  int n=s.nextInt();
        for(int i=1; i <= 10; i++)
        {
            System.out.println(n+" * "+i+" = "+n*i);
        }
    }
}

Sample Input/output:
Enter number:7
7 * 1 = 7
7 * 2 = 14
7 * 3 = 21
7 * 4 = 28
7 * 5 = 35
7 * 6 = 42
7 * 7 = 49
7 * 8 = 56
7 * 9 = 63
7 * 10 = 70
21) Java Program to Reverse a Number and find the Sum of its Digits Using do-while Loop. 

import java.util.*;
public class Use_Do_While
{
    public static void main(String[] args)
    {
        int n, a, m = 0, sum = 0;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter any number:");
        n = s.nextInt();
        do
        {
            a = n % 10;
            m = m * 10 + a;
            sum = sum + a;
            n = n / 10;
        }
        while( n > 0);
        System.out.println("Reverse:"+m);
        System.out.println("Sum of digits:"+sum);
    }
}
22) java program to print without main function.

import java.util.*;
public class Without_Main 
{
    static 
    {
         System.out.println("Hello World!!");
         System.exit(0);
    } 
    /*Does not work with JDK7*/
}

Sample output:
Hello World!!
23) java program to return value using a method.

import java.util.*;
public class Return_Value
{
    void input()
    {
        int x, y, z;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter first integer:");
        x = s.nextInt();
        System.out.print("Enter second integer:");
        y = s.nextInt();
        z = add(x, y);
        System.out.println("Result:"+z);
    }
    int add(int a, int b)
    {
        int c;
        c = a + b;
        return c;
    }
    public static void main(String[] args) 
    {
        Return_Value obj = new Return_Value();
        obj.input();
    }
}

sample Input:
Enter first integer:5
Enter second integer:6

sample output:
Result:11
24) java code to find the byte sum of two integer values.

import java.util.*;
public class Byte_Sum
{
    public static void main(String[] args) 
    {
        byte a, b;
        int x, y, z;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter first byte value:");
        a = s.nextByte();
        x = a;
        System.out.print("Enter second byte value:");
        b = s.nextByte(); 
        y = b;
        z = x + y;
        System.out.println("Result:"+z);
     }
}

Sample input:
Enter first byte value:124
Enter second byte value:115

Sample output:
Result:239
25) java program to print the statement without using semi-colon at the end.

import java.util.*;
public class Print_Without_Semicolon 
{
     public static void main(String[] args) 
     {
        int i = 0;
        if(System.out.printf("Hi people!! ") == null) {}
        for(i = 1; i < 2; System.out.println("the text is Hello World."))
        {
            i++;
       }
     }
}

Sample output:
Hi people!! the text is Hello World.
25) Java Program to Compute GCD.

import static java.lang.StrictMath.min;
import java.util.*;
public class GCD
{
    public static void main(String args[])
    {
        int a, b, GCD = 1;
        Scanner s = new Scanner(System.in);
        System.out.print("Enter First Number:");
        a = s.nextInt();
        System.out.print("Enter Second Number:");
        b = s.nextInt();
        int n = min(a,b);
        for(int i = 2; i < n; i++)
        {
            while(a % i == 0 && b % i==0)
            {
                GCD = GCD * i;
                a = a / i;
                b = b / i;
            }
        }
        System.out.println("Greatest Common Divisor:"+GCD);
    }
}

Sample input:
Enter First Number:24
Enter Second Number:16

Sample output:
Greatest Common Divisor:8
26) java program to print sum of n natural numbers

import java.util.*;
public class Natural 
{
    public static void main(String args[])
    {
        int x, i = 1 ;
        int sum = 0;
        System.out.println("Enter Number of items :");
        Scanner s = new Scanner(System.in);
        x = s.nextInt();
        while(i <= x)
        {
            sum = sum +i;
            i++;
        }
        System.out.println("Sum of "+x+" numbers is :"+sum);
    } 
}
 
sample input:
Enter Number of items :
55

Sample output:
Sum of 55 numbers is :1540
27) java program to print the perfect squares between 1 to n

class CountSquares {

static int countSquares(int a, int b) 

    {

int cnt = 0;

for (int i = a; i <= b;

for (int j = 1; j * j <= i; j++)

if (j * j == i) 

                    cnt++;

return cnt; 

    } 
}

public class PerfectSquares {

public static void main(String[] args) 

    {

int a = 1, b = 25;

CountSquares obj = new CountSquares();

System.out.print("Count of squares is " + obj.countSquares(a, b)); 

       } 
} 
Head count of birds and animals

import java.util.*;
public class Main {

    public static void main(String[] args) 
{

  Scanner sc=new Scanner(System.in);
  int heads=sc.nextInt();
  int legs=sc.nextInt();
  int birds=0;
  for(birds=0;birds<=heads;birds++)
  {
      if(birds*2+(heads-birds)*4==legs)
      {
          System.out.print(birds+" ");
          System.out.print(heads-birds);
      }
  }
 }
}

input 1:
27 84

output 1:
12 15
Interlace between even and odd integers:

import java.util.*;
public class MyClass 
{
    public static void main(String args[]) 
    {
        Scanner sc=new Scanner(System.in);
        int num1=sc.nextInt();
        int num2=sc.nextInt();

        for(int index1=num1,index2=num2;index1<=num2;index1++,index2--)
        {
            if(index1%2==1)
               System.out.print(index1+" ");
            if(index2%2==0)
               System.out.print(index2+" ");
        }
    }
}

input 1:
5
11

output 1:
5 10 7 8 9 6 11 
Print days in a Month:

import java.util.*;
public class Main
{
    public static void main(String[] args)
    {
Scanner sc=new Scanner(System.in);
int n=sc.nextInt();
if(n>=13)
System.out.print("Invalid");
else if(n==1)
System.out.print("31");
else if(n==2)
System.out.print("28");
else if(n==3)
System.out.print("31");
else if(n==4)
System.out.print("30");
else if(n==5)
System.out.print("31");
else if(n==6)
System.out.print("30");
else if(n==7)
System.out.print("31");
else if(n==8)
System.out.print("31");
else if(n==9)
System.out.print("30");
else if(n==10)
System.out.print("31");
else if(n==11)
System.out.print("30");
else if(n==12)
System.out.print("31");
}
} 

input 1:
5
output 1:
31

input 2:
15
output 2:
Invalid
Print the sum of ASCII values:

import java.util.*;
public class Hello 
{
    public static void main(String[] args)
    {
   Scanner sc=new Scanner(System.in);
  String str=sc.next();
  int l=str.length();
  int sum=0;
  for(int index=0;index<l;index++)
  {
      sum+=(int)str.charAt(index);
  }
  System.out.print(sum);
 }
}

input 1:
abcde
output 1:
495

input 2:
abcd
output 2:
394
Print equivalent numerical values of characters of a string:

import java.util.*;
public class Main 
{
    public static void main(String args[])
    {
      Scanner sc=new Scanner(System.in);
      String str=sc.next();
      for(int index=0;index<str.length();index++)
      {
          System.out.print(Character.getNumericValue(str.charAt(index))+" ");
      }
    }
}

input 1:
abcde
output 1:
10 11 12 13 14 

input 2:
mnop
output 2:
22 23 24 25
Count number of flips to convert A to B:

import java.util.*;
public class Main
{
    public static void main(String[] args)
    {
   Scanner sc=new Scanner(System.in);
  int a=sc.nextInt();
  int b=sc.nextInt();
  int num=a^b,count=0;
  while(num!=0)
  {
      count+=num&1;
      num>>=1;
  }
  System.out.print(count);
 }
}

input 1:
10 20
output 1:
4

input 2:
12 10
output 2:
2

explanation:
binary representation of 12 is 1100 and 10 is 1010. hece two bits are to be flipped to convert A to B.
Number series Ap progression - find Nth term:

import java.util.Scanner;
public class Main
{
  public static void main(String[] args) 
 {
  Scanner sc=new Scanner(System.in);
  int a=sc.nextInt();
  int b=sc.nextInt();
  int c=sc.nextInt();
  int d=sc.nextInt();
  int k=sc.nextInt();
  int diff1=c-a;
  int diff2=d-b;
  int num1=a,num2=b;
  for(int index=1;index<=k-2;index++)
  {
      if(index%2==1)
      {
          num1=num1+diff1;
      }
      else
      {
          num2=num2+diff2;
      }
  }
  if(k%2==0)
  System.out.print(num2);
  else
  System.out.print(num1);
 }
}

input 1:
1 1 5 4
10
output 1:
13

input 2:
2 1 4 7
7
output 2:
5