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Thread: Array help

  1. #1
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    Default Array help

    Hi, i am having trouble getting the following String array to run correctly and having compile error. My compile error is posted below.



    stapler.java:94: error: cannot find symbol
    System.out.println("Product name: " +stapler.getnames[0]);
    ^
    symbol: variable getnames
    location: variable stapler of type Stapler
    stapler.java:105: error: cannot find symbol
    System.out.println("Product name: " +stapler1.getnames[1]);
    ^
    symbol: variable getnames
    location: variable stapler1 of type Stapler
    stapler.java:116: error: cannot find symbol
    System.out.println("Product name: " +stapler2.getnames[2]);
    ^
    symbol: variable getnames
    location: variable stapler2 of type Stapler
    3 errors







     
     
    public class Stapler {
     
    		String[] name;
    		int numberItem;
    		double inStock;
    		double price;
     
     
    		int numberItem1;
    		double inStock1;
    		double price1;
     
     
    		int numberItem2;
    		double inStock2;
    		double price2;
     
    			public String[] getnames(){
    			return(name);
    			}
    				public int getItemnumber(){
    				return(numberItem);
    				}
    					public double getprices(){
    					return(price);
    					}
    						public double getunits(){
    						return(inStock);
    						}	
    							public double getVolume() {
    							return (inStock * price);
    							}
     
    				public int getItemnumber1(){
    				return(numberItem1);
    				}
    					public double getprices1(){
    					return(price1);
    					}
    						public double getunits1(){
    						return(inStock1);
    						}	
    							public double getVolume1() {
    							return (inStock1 * price1);
    							}
     
     
     
    				public int getItemnumber2(){
    				return(numberItem2);
    				}
    					public double getprices2(){
    					return(price2);
    					}
    						public double getunits2(){
    						return(inStock2);
    						}	
    							public double getVolume2() {
    							return (inStock2 * price2);
    							}			
     
     
    	Stapler(){
    		String[] name = {"Miller's Stapler", "Miller's Staples", "Miller's Paper"};
    		numberItem = 123456;
    		inStock = 123;
    		price = 4.75;
     
     
    		numberItem1 = 654321;
    		inStock1 = 321;
    		price1 = 2.50;
     
     
     
    		numberItem2 = 987654;
    		inStock2 = 987;
    		price2 = 1.37;
    		}
     
     
     
    	public static void main(String[] args) {
    		Stapler stapler, stapler1, stapler2;
     
    			stapler = new Stapler();
     
    			stapler1 = new Stapler();
     
    			stapler2 = new Stapler();
     
    	System.out.println("Product name: " +stapler.getnames[0]);
     
    	System.out.println("Product Number: "+stapler.getItemnumber());
     
    	System.out.println("Price of one product: "+stapler.getprices());
     
    	System.out.println("Number of units in stock: "+stapler.getunits());	
     
    	System.out.println("Total value of Staplers is: "+stapler.getVolume());
    	System.out.println();
    	//
    	System.out.println("Product name: " +stapler1.getnames[1]);
     
    	System.out.println("Product Number: "+stapler1.getItemnumber1());
     
    	System.out.println("Price of one product: "+stapler1.getprices1());
     
    	System.out.println("Number of units in stock: "+stapler1.getunits1());	
     
    	System.out.println("Total value of Staplers is: "+stapler1.getVolume1());
    	System.out.println();
    	//
    	System.out.println("Product name: " +stapler2.getnames[2]);
     
    	System.out.println("Product Number: "+stapler2.getItemnumber2());
     
    	System.out.println("Price of one product: "+stapler2.getprices2());
     
    	System.out.println("Number of units in stock: "+stapler2.getunits2());	
     
    	System.out.println("Total value of Staplers is: "+stapler2.getVolume2());
    	System.out.println();
    	}
    }


  2. #2
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    Default Re: Array help

    Hi,

    Could you please see the below syntax.

    System.out.println("Product name: " +stapler.getnames()[0]);

    Regards
    Lakshmi M

  3. #3
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    Default Re: Array help

    This is my new code:
     
    public class Stapler {
     
    		String[] name;
    		int[] numberItem;
    		double[] inStock;
    		double[] price;
     
     
    			public String[] getnames(){
    			return(name);
    			}
    				public int[] getItemnumber(){
    				return(numberItem);
    				}
    					public double[] getprices(){
    					return(price);
    					}
    						public double[] getunits(){
    						return(inStock);
    						}	
    							public double getVolume() {
    							return (inStock[0] * price[0]);
    							}
     
     
     
     
    							public double getVolume1() {
    							return (inStock[1] * price[1]);
    							}
     
     
    							public double getVolume2() {
    							return (inStock[2] * price[2]);
    							}	
     
    			public double getTotal() {
    			return (price[2]*inStock[2]+price[1]*inStock[1]+price[0]*inStock[0]);
    			}
     
     
    	Stapler(){
    		String[] name = {"Miller's Stapler", "Miller's Staples", "Miller's Paper"};
    		int[] numberItem = {123456, 654321, 987654};
    		int[] inStock = {123, 321, 987};
    		double[] price = {4.75, 2.50, 1.37};
     
    		}
     
     
     
    	public static void main(String[] args) {
    		Stapler stapler, stapler1, stapler2;
     
    			stapler = new Stapler();
     
    			stapler1 = new Stapler();
     
    			stapler2 = new Stapler();
     
     
     
     
    	System.out.println("Product name: " +stapler.getnames()[0]);
     
    	System.out.println("Product Number: " +stapler.getItemnumber()[0]);
     
    	System.out.println("Price of one product: "+stapler.getprices()[0]);
     
    	System.out.println("Number of units in stock: "+stapler.getunits()[0]);	
     
    	System.out.println("Total value of Staplers is: "+stapler.getVolume());
    	System.out.println();
    	//
    	System.out.println("Product name: " +stapler1.getnames()[1]);
     
    	System.out.println("Product Number: "+stapler1.getItemnumber()[1]);
     
    	System.out.println("Price of one product: "+stapler1.getprices()[1]);
     
    	System.out.println("Number of units in stock: "+stapler1.getunits()[1]);	
     
    	System.out.println("Total value of Staplers is: "+stapler1.getVolume1());
    	System.out.println();
    	//
    	System.out.println("Product name: " +stapler2.getnames()[2]);
     
    	System.out.println("Product Number: "+stapler2.getItemnumber()[2]);
     
    	System.out.println("Price of one product: "+stapler2.getprices()[2]);
     
    	System.out.println("Number of units in stock: "+stapler2.getunits()[2]);	
     
    	System.out.println("Total value of Staplers is: "+stapler2.getVolume2());
    	System.out.println();
     
    	System.out.println("Total value of all inventory is: "+stapler.getTotal());
     
    	}
    }
    I get this error when i run it:
    Exception in thread "main" java.lang.NullPointerException
    at Stapler.main(stapler.java:67)
    How do i fix it.

  4. #4
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    Default Re: Array help

    Hi, you are not assigned the values to instance variables in 'no argument constructor'. Please assing the values to instance variable in no argument construcor like

    Stapler() {
    name = {"Miller's Stapler", "Miller's Staples", "Miller's Paper"}
    numberItem = {123456, 654321, 987654};
    inStock = {123, 321, 987};
    price = {4.75, 2.50, 1.37};
    }

  5. #5
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    Default Re: Array help

    The constructor is already assinged those variables. so you pretty much told me to change nothing and it would work. That is not helpful.

  6. #6
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    Default Re: Array help

    Exception in thread "main" java.lang.NullPointerException
    at Stapler.main(stapler.java:67)
    Line 67 had a variable with a null value when it was executed. Look at line 67, find the variable with the null value and backtrack in the code to see why that variable does not have a valid value.
    If you don't understand my answer, don't ignore it, ask a question.

  7. #7
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    Default Re: Array help

    I cannot find any variable that could cause it to be a null value. I have checked all the code and nothing is jumping out at me. Could it be wrong placment of code?

  8. #8
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    Default Re: Array help

    If you can not see what variable online 67 is null, let the computer tell you.
    Add a println statement just before statement 67 that prints out the values of all the variables used on line 67. The print out will show you which variable is null.

    Could it be wrong placment of code?
    Yes. The program is using a variable that has not been given a value and is still null.
    If you don't understand my answer, don't ignore it, ask a question.

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