Answers for "patterns in java"

java design patterns

// double locking is used to reduce the overhead of the synchronized method
public static ThreadSafeSingleton getInstanceDoubleLocking() {
	if (instance == null) {
		synchronized (ThreadSafeSingleton.class) {
			if (instance == null) {
				instance = new ThreadSafeSingleton();
			}
		}
	}
	return instance;
}

java design patterns

// double locking is used to reduce the overhead of the synchronized method
public static ThreadSafeSingleton getInstanceDoubleLocking() {
	if (instance == null) {
		synchronized (ThreadSafeSingleton.class) {
			if (instance == null) {
				instance = new ThreadSafeSingleton();
			}
		}
	}
	return instance;
}

make pattern for V in jaca

void drowV(int hight){
    int rowLen = (hight-1)*2;

    for(int i=0; i<hight; i++){
        int start = i;
        int end = rowLen-i;
        for(int j=0;j<=rowLen; j++){
            if(j==end){
                System.out.println("*");
                break;
            }
            else if(j==start){
                System.out.print("*");
            }
            else{
                System.out.print(" ");
            }
        }
    }
}

make pattern for V in jaca

void drowV(int hight){
    int rowLen = (hight-1)*2;

    for(int i=0; i<hight; i++){
        int start = i;
        int end = rowLen-i;
        for(int j=0;j<=rowLen; j++){
            if(j==end){
                System.out.println("*");
                break;
            }
            else if(j==start){
                System.out.print("*");
            }
            else{
                System.out.print(" ");
            }
        }
    }
}

pyramid pattern in java

// Java implementation to print the 
// following pyramid pattern 
public class Pyramid_Pattern { 
  
    // function to print the following pyramid 
    // pattern 
    static void printPattern(int n) 
    { 
        int j, k = 0; 
  
        // loop to decide the row number 
        for (int i = 1; i <= n; i++) { 
              
            // if row number is odd 
            if (i % 2 != 0) { 
              
                // print numbers with the '*'  
                // sign in increasing order 
                for (j = k + 1; j < k + i; j++) 
                    System.out.print(j + "*"); 
                System.out.println(j++); 
  
                // update value of 'k' 
                k = j; 
            } 
  
            // if row number is even 
            else { 
                 
                // update value of 'k' 
                k = k + i - 1; 
  
                // print numbers with the '*' in 
                // decreasing order 
                for (j = k; j > k - i + 1; j--) 
                    System.out.print(j + "*"); 
                System.out.println(j); 
            } 
        } 
    } 
  
    // Driver program to test above 
public static void main(String args[]) 
    { 
        int n = 5; 
        printPattern(n); 
    } 
}

pyramid pattern in java

// Java implementation to print the 
// following pyramid pattern 
public class Pyramid_Pattern { 
  
    // function to print the following pyramid 
    // pattern 
    static void printPattern(int n) 
    { 
        int j, k = 0; 
  
        // loop to decide the row number 
        for (int i = 1; i <= n; i++) { 
              
            // if row number is odd 
            if (i % 2 != 0) { 
              
                // print numbers with the '*'  
                // sign in increasing order 
                for (j = k + 1; j < k + i; j++) 
                    System.out.print(j + "*"); 
                System.out.println(j++); 
  
                // update value of 'k' 
                k = j; 
            } 
  
            // if row number is even 
            else { 
                 
                // update value of 'k' 
                k = k + i - 1; 
  
                // print numbers with the '*' in 
                // decreasing order 
                for (j = k; j > k - i + 1; j--) 
                    System.out.print(j + "*"); 
                System.out.println(j); 
            } 
        } 
    } 
  
    // Driver program to test above 
public static void main(String args[]) 
    { 
        int n = 5; 
        printPattern(n); 
    } 
}