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Top Beginner Patterns in Java: How to Print Star, Number and Character (Lecture 5)

 Java - Introduction to Programming

Lecture 5



Patterns - Part 1





import java.util.*;

 

public class Patterns {

   public static void main(String args[]) {

       int n = 5;

       int m = 4;

       for(int i=0; i<n; i++) {

           for(int j=0; j<m; j++) {

               System.out.print("*");

           }

           System.out.println();

       }

   }

}

 










import java.util.*;

 

public class Patterns {

   public static void main(String args[]) {

       int n = 5;

       int m = 4;

       for(int i=0; i<n; i++) {

           for(int j=0; j<m; j++) {

               if(i == 0 || i == n-1 || j == 0 || j == m-1) {

                   System.out.print("*");

               } else {

                   System.out.print(" ");

               }

           }

           System.out.println();

       }

   }

}

 















import java.util.*;

 

public class Patterns {

   public static void main(String args[]) {

       int n = 4;

      

       for(int i=1; i<=n; i++) {

           for(int j=1; j<=i; j++) {

                   System.out.print("*");

           }

           System.out.println();

       }

   }

}

 
















import java.util.*;

 

public class Patterns {

   public static void main(String args[]) {

       int n = 4;

      

       for(int i=n; i>=1; i--) {

           for(int j=1; j<=i; j++) {

                   System.out.print("*");

           }

           System.out.println();

       }

   }

}

 












import java.util.*;

 

public class Patterns {

   public static void main(String args[]) {

       int n = 4;

      

       for(int i=n; i>=1; i--) {

           for(int j=1; j<i; j++) {

               System.out.print(" ");

           }

 

           for(int j=0; j<=n-i; j++) {

               System.out.print("*");

           }

           System.out.println();

       }

   }

}

 












import java.util.*;

 

public class Patterns {

   public static void main(String args[]) {

       int n = 5;

      

       for(int i=1; i<=n; i++) {

           for(int j=1; j<=i; j++) {

               System.out.print(j);

           }

           System.out.println();

       }

   }

}

 











import java.util.*;

 

public class Patterns {

   public static void main(String args[]) {

       int n = 5;

      

       for(int i=n; i>=1; i--) {

           for(int j=1; j<=i; j++) {

               System.out.print(j);

           }

           System.out.println();

       }

   }

}

 









import java.util.*;

 

public class Patterns {

   public static void main(String args[]) {

       int n = 5;

       int number = 1;

 

       for(int i=1; i<=n; i++) {

           for(int j=1; j<=i; j++) {

               System.out.print(number+" ");

               number++;

           }

           System.out.println();

       }

   }

}

 












import java.util.*;

 

public class Patterns {

   public static void main(String args[]) {

       int n = 5;

 

       for(int i=1; i<=n; i++) {

           for(int j=1; j<=i; j++) {

               if((i+j) % 2 == 0) {

                   System.out.print(1+" ");

               } else {

                   System.out.print(0+" ");

               }

           }

           System.out.println();

       }

   }

}

 












Homework Problems (Solutions in next Lecture’s Video)

  1. Print a solid rhombus.






  1. Print a number pyramid.






  1. Print a palindromic number pyramid.









Homework Solution (Lecture 4)


  1. Print all even numbers till n.


  1. public class Solutions {

  2.    public static void main(String args[]) {

  3.        int n = 25;

  4.  

  5.        for(int i=1; i<=n; i++) {

  6.            if(i % 2 == 0) {

  7.                System.out.println(i);

  8.            }

  9.        }

  10.    }   

  11. }

  12.  


    3.  Make a menu driven program. The user can enter 2 numbers, either 1 or 0. 

If the user enters 1 then keep taking input from the user for a student’s marks(out of 100). 

If they enter 0 then stop.

If he/ she scores :

Marks >=90 -> print “This is Good”

89 >= Marks >= 60 -> print “This is also Good”

59 >= Marks >= 0 -> print “This is Good as well”

Because marks don’t matter but our effort does.

(Hint : use do-while loop but think & understand why)


import java.util.*;

 

public class Solutions {

   public static void main(String args[]) {

       Scanner sc = new Scanner(System.in);

       int input;

 

       do {

           int marks = sc.nextInt();

           if(marks >= 90 && marks <= 100) {

               System.out.println("This is Good");

           } else if(marks >= 60 && marks <= 89) {

               System.out.println("This is also Good");

           } else if(marks >= 0 && marks <= 59) {

               System.out.println("This is Good as well");

           } else {

               System.out.println("Invalid");

           }

 

           System.out.println("Want to continue ? (yes(1) or no(0))");

           input = sc.nextInt();

      

       } while(input == 1);

   }   

}

 


Qs. Print if a number n is prime or not (Input n from the user). 

[In this problem you will learn how to check if a number is prime or not]

import java.util.*;

 

public class Solutions {

   public static void main(String args[]) {

       Scanner sc = new Scanner(System.in);

       int n = sc.nextInt();

 

       boolean isPrime = true;

       for(int i=2; i<=n/2; i++) {

           if(n % i == 0) {

               isPrime = false;

               break;

           }

       }

 

       if(isPrime) {

           if(n == 1) {

               System.out.println("This is neither prime not composite");

           } else {

               System.out.println("This is a prime number");

           }

       } else {

           System.out.println("This is not a prime number");

       }

   }   

}

 

  


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