Control Structure or Loop in Java

Author - Shiva Gautam
9/12/2019
10
It is used to enumerate range based data, repeated data and large data manipulation using single repeatable code.

we can easily control large statement hence it is called Control Statement.

Control Statement Will Work using three different substatements.
                               
                                    Forward                    Backward

 Initialization             i=min                         i= max 


Condition                  i<=max                      i>=min


Iteration                    i++                               i--

Loop:-  Process of Control Structure is called loop because it will execute until condition false
Type of Control Structure in java:-

 1.1 Entry Control:-  First Check Condition then execute statement

 1.1.1   For Loop  

 1.1.2   While Loop

 1.1.3    For-each Loop
1.2 Exit Control:-  First execute statement then check the condition

 1.2.1  Do--while:-

 Syntax:

 init;
do
{
   statement;
   increment|decrement;

 }while(condition);
WAP to Print Sum of two-digit positive number in a range?

 class Dowhile
{
   public static void main(String args[])
   {
       int i;
       i=99;
       int sum=0;
       do
       {
         sum+=i;   //sum=0+10 //sum= 10+11
         i--;
       }while(i>=10); 

        System.out.println(sum);

    }

}



Q1 WAP to print 1 to 5 and 5 to1 using single do--while loop?
1
2
3
4
5
5
4
3
2
1
Q2 WAP to calculate factorial with complete expression?

 5! = 5*4*3*2*1=120
Q3 WAP to reverse mobile number and find max digit in the mobile number and count repeated digit and show number is VIP or not according to number combination?
While Structure:-

 init;
while(condition)
{
     statement;
     iteration;

 }

First Check Condition then execute the statement.

 while loop mostly used for the in-finite loop-based program.
WAP to print 1 to 10 using the finite loop and infinite loop both?

 i=1;
while(i<10)
{
    System.out.println(i);
    i++;

 }
...............................................................
boolean a=true
int i=1;
while(a)
{

 System.out.println(i++);
if(i>10)
flag=false;

 }
Limitation of While Loop:-

 1 Complex structure hence for nested sequence it can not be used easily.

For Loop:-
It provides a simple syntax structure and defines all sub statement using a single statement.

        1     2    5            4  7
for(init;condition;iteration)
{
     3  6
     statement
}
we can create finite program using for loop.


ASSIGNMENT:-

 1) WAP to display series of a prime number?

 2) WAP to print sum of one digit and 2 digits negative number using a single while loop and for loop?

 0 to 9
-99 to -10

class Sumwhile
{
   public static void main(String args[])
   {
      int i,j;
      i=-99;
      j=1;
      int sum1=0; 
      int sum2=0;
      int sum=0;
      while(i<=-10)
      {
         if(j<10)
         sum1=sum1+j;
         j++;
         sum2=sum2+i;   
         i++;

       }
     sum=sum1+sum2;
     System.out.println(sum);

     }

 }



Q)WAP to print only Fibonacci series in Java ?

 class Faboprime
{
    public static void main(String args[])
    {
          int a=-1,b=1;
          int c;
          int i=1;
          while(i<=10)
          {
                 c=a+b;   
                 System.out.println(c);
                 a=b;   
                 b=c;   
                 i++;
           }

     } 
}


............................................................................................
Q)Q)WAP to print prime number only in  Fibonacci series in Java ?
Logic1)

class Faboprime
{
    public static void main(String args[])
    {
          int a=-1,b=1;
          int c;
          int i=1;
         
          while(i<=10)
          {
                 c=a+b;   
                 int j=2;
                 while(j<c)
                 {
                     if(c%j==0)
                       break;
                     j++;

                  }
                 if(c==j)
                 System.out.println(c);
                 a=b;   
                 b=c;   
                 i++;
           }

     } 
}

 ..............................................................................................
Logic2)
class Faboprime
{
    public static void main(String args[])
    {
          int a=-1,b=1;
          int c;
          int i=1;
         
          while(i<=10)
          {
                 c=a+b;   
                 int j=1;
                 int count=0;
                 while(j<=c)
                 {
                     if(c%j==0)
                       count++;
                     j++;

                  }
                 if(count==2)
                 System.out.println(c);
                 a=b;   
                 b=c;   
                 i++;
           }

     } 
}

 Logic3)

 class Faboprime
{
    public static void main(String args[])
    {
          int a=-1,b=1;
          int c;
          int i=1;
         
          while(i<=10)
          {
                 c=a+b;   
                 int j=2;
                 boolean f=true;
                 while(j<c)
                 {
                     if(c%j==0)
                     {
                       f=false;
                       break;
                     }  
                     j++;

                  }
                 if(f && c>=2)
                 System.out.println(c);
                 a=b;   
                 b=c;   
                 i++;
           }

     } 

}



Design4)
class Faboprime
{
    public static void main(String args[])
    {
          int a=-1,b=1;
          int c;
         
         
        for( int i=1;i<=10;i++)
          {
                 c=a+b;   
                 boolean f=true;
                for(int j=2;j<c;  j++)
                 {
                     if(c%j==0)
                     {
                       f=false;
                       break;
                     }  
                 }
                 if(f && c>=2)
                 System.out.println(c);
                 a=b;   
                 b=c;   
               
           }

     } 
}

 ..............................................................................................................................

 1) WAP to print 1 to 5 , 5 to 1 and 5 to 1 and 1 to 5 using single while loop and for loop?

2) WAP to print pattern
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5
3) WAP  to print this pattern?

 A B C D E
A B C D
A B C
A B
A
......................................................................

 4 ) WAP to print this pattern?

 A a B b C
A a B b
A a B
A a
A

 5 ) WAP to print this pattern?

 1 0 0 1 0
1 0 0 1
1 0 0
1 0
1
..............................................................................................................











Shiva Gautam

Shiva Gautam

Hi, I'm Shiva Gautam. With over 15 years of diverse experience in various IT domains, I am now an entrepreneur focusing on both training and software development. My expertise spans across multiple technologies, and I've authored numerous articles on subjects including Java, Python, REACT, NODE, ANGULAR, Cloud, software testing, Django framework, C#, Flutter, Salesforce, Ruby on Rails, .NET, AWS, DEVOPS, AI/ML and more. For additional information, please visit shivaconceptsolution.com and kangaroosoftware.net.

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10Comments

POST Answer of Questions and ASK to Doubt

  1. Mohd FaheemSeptember 14, 2019 at 5:36 PM

    Solution 2
    class Fact
    {
    public static void main(String args[])
    {
    int num=5,fact=1;
    System.out.print(num+"! = ");
    do
    {
    System.out.print(num);
    fact=num*fact;
    num--;
    if(num>0)
    System.out.print("*");
    }while(num>0);
    System.out.print(" ="+fact);
    }
    }

    ReplyDelete
  2. Mohd FaheemSeptember 14, 2019 at 5:37 PM

    Solution 1
    class Print
    {
    public static void main(String args[])
    {
    int i=1,j=5;
    do
    {
    if(i<=5)
    {
    System.out.println(i);

    }
    else
    {
    System.out.println(j);
    j--;
    }
    i++;


    }while(i<=10);
    }
    }

    ReplyDelete
  3. Mohd FaheemSeptember 14, 2019 at 5:37 PM

    Solution 3
    import java.util.Scanner;
    class Check
    {
    public static void main(String args[])
    {
    Scanner sc=new Scanner(System.in);
    int j=0;
    System.out.println("Enter mobile no.");
    int num=sc.nextInt();
    int max=num%10;
    System.out.print("Reverse of no. = ");
    do
    {
    int i=num%10;
    System.out.print(i);
    num=num/10;
    j=num%10;
    if(j>max)
    max=j;

    }while(num>0);

    System.out.println("\nMaximum digit ="+max);
    }


    }

    ReplyDelete
  4. Java ZimSeptember 16, 2019 at 4:47 PM

    public class Forprime
    {
    public static void main(String args[])
    {
    int i=1;
    int j=2;
    int conter=0;
    for (i=1;i<=20; i++)
    {
    conter=0;
    for(j=2; j<=i/2; j++)
    {
    if (i%j==0)
    {
    conter++;
    break;
    }
    }

    if(conter==0)
    {
    System.out.println(i);
    }
    }
    }
    }

    ReplyDelete
  5. Mohd FaheemSeptember 19, 2019 at 6:30 PM

    Solution to print pattern
    class Pattern1
    {
    public static void main(String args[])
    {
    int i=1,j=0;
    while(i<=6)
    {
    j=1;
    while(j<i)
    {
    System.out.print(j);
    j++;
    }
    i++;
    System.out.print("\n");
    }
    }
    }

    ReplyDelete
  6. Mohd FaheemSeptember 19, 2019 at 6:31 PM

    Solution to print pattern 1
    class P1
    {
    public static void main(String args[])
    {
    int i=1,j=5,k=5,m=1;
    while(i<20)
    {
    if(i<=5)
    {
    System.out.println(i);
    i++;
    }
    else if(j>=1)
    {
    System.out.println(j);
    j--;
    }
    else if(k>=1)
    {
    System.out.println(k);
    k--;
    }
    else if(m<=5)
    {
    System.out.println(m);
    m++;
    }

    }
    }
    }

    ReplyDelete
  7. RehanSeptember 21, 2019 at 11:33 AM

    import java.util.Scanner;
    class Mobileno
    {
    public static void main(String args[])
    {
    Scanner sc = new Scanner(System.in);
    int mb,i,rev=0,temp,temp1,temp2,rem,rep,rep1,max=1,count=0;
    System.out.println("Enter your mobile number");
    mb=sc.nextInt();
    System.out.println("enter the number to check repeatation");
    rep=sc.nextInt();
    temp=mb;
    temp2=mb;
    do
    {
    temp1=temp%10;
    temp=temp/10;
    if(temp1>max)
    max=temp1;
    }while(temp>0);
    System.out.println("The maximum digit in mobile number is :"+max);
    do
    {
    rem=mb%10;
    rev=rev*10+rem;
    mb=mb/10;


    }while(mb!=0);
    System.out.println("the reversed number :"+rev);
    for(i=1;i<=10;i++)
    {
    if(temp2%10==rep)
    {
    ++count;
    }
    temp2=temp2/10;
    }
    System.out.println(rep+" is repeated "+count+" times");
    if(count>=4)
    System.out.println("the Entered no. is VIP");
    }
    }

    ReplyDelete
  8. Mohd FaheemSeptember 22, 2019 at 11:07 PM

    pattern 10010

    class Pattern2
    {
    public static void main(String args[])
    {
    int i=1,j=0,count=0;
    while(i<=5)
    {
    j=1;count=0;
    while(j<=i)
    {
    if(i%j==0)
    count++;

    if(count==2)
    System.out.print("1");
    else
    System.out.print("0");
    j++;
    }
    i++;
    System.out.print("\n");
    }
    }
    }

    ReplyDelete
  9. Mohd FaheemSeptember 22, 2019 at 11:07 PM

    pattern ABCDE

    class Pattern
    {
    public static void main(String args[])
    {
    char a='A';
    int i=5;
    for(;i>=1;)
    {
    for(int j=1;j<=i;j++)
    {
    System.out.print(a);
    a++;
    }
    System.out.print("\n");
    a='A';
    i--;
    }
    }
    }

    ReplyDelete
  10. Mohd FaheemSeptember 22, 2019 at 11:08 PM

    pattern AaBbC

    class Pattern
    {
    public static void main(String args[])
    {
    char a='A',b='a';
    int i,j;
    for(i=5;i>=1;i--)
    {
    a='A';b='a';
    for(j=1;j<=i;j++)
    {
    if(j%2!=0)
    {
    System.out.print(a);
    a++;
    }
    else
    {
    System.out.print(b);
    b++;
    }
    }
    System.out.println();
    }
    }
    }

    ReplyDelete
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