java - Having trouble initializing an ArrayList of Objects inside a constructor -

hi have neuralnetwork class, constructor should initialize:

• a 2-dimensional double array, double[# of rows in .data file][# of numbers in each row]
• [# of numbers in each row] - 1 inputnodes
• 2/3 (rounded down) * # of hiddennodes
• 1 output node (which hiddennode object) takes in hiddennodes

what having trouble with

• having java create inputnodes, hiddennodes, , outputnode automatically based on data given, far have manually create nodes

the inputnodes stored in either array list or array, , passed constructor parameters of hiddennode, hiddennode can take parameters of:

hiddennode(node[] nodes) node object superclass of hiddennode , inputnode

here code have far constructor:

neuralnetwork.java

/*  * these values neuralnetwork constructor  */ private final string comma = ","; private final string qmarks = "?"; private list<inputnode> input = new arraylist<inputnode>(); // input nodes private list<hiddennode> hiddennodelayer = new arraylist<hiddennode>(); // arraylist of hiddennode[] arrays private list<hiddennode> outputnode = new arraylist<hiddennode>();  public neuralnetwork(file f){       try {         @suppresswarnings("resource")         scanner infile = new scanner(f);          int noofnodes;          //while there line in infile.         while (infile.hasnextline()){             //store line string line             string line = infile.nextline();             //system.out.println(line);//test code see file looks             //parition values separated comma             string[] numbers = line.split(comma);             //system.out.println(arrays.tostring(columns)); //test code see length of each column             /*code works , prints out row             * */             /*              * initialize noofnodes length of numbers - 1              */             noofnodes = numbers.length - 1;              //counter number of rows in .data file             int noofrowsindata = 0;                //this count number of rows in .data file             linenumberreader lnr = new linenumberreader(new filereader(f));             try {                 lnr.skip(long.max_value);                 noofrowsindata = lnr.getlinenumber();                 lnr.close();             } catch (ioexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             }              data = new double[noofrowsindata][numbers.length];             //system.out.println(data[0].length); //test code works properly, , prints numbers.length              //copy on data form .data file             (int = 0; < data.length; i++) {                 (int j = 0; j < data[i].length; j++) {                     // each row...                     if (!numbers[j].equals(qmarks)) {                         // if values in each row not equal "?"                         // set rows[i] values in column[i]                         data[i][j] = double.parsedouble(numbers[j]);                         //system.out.println(data[i][j]); //test code see what's printed here                     } else {                         data[i][j] = 0;                         //system.out.println(data[i][j]); //test code see what's printed here                     }                 }             }         }          //system.out.println(data.length); //see length of data double array is. works         //test code print out 2-d double array , see being stored //          for(int = 0; < data.length; i++) { //              system.out.println("for row[" + + "] of file:"); //works //              (int j = 0; j < data[i].length; j++) { //                 system.out.println("   data[" + + "][" +  //              j + "] = " + data[i][j]); //works //              }  //          }      } catch (filenotfoundexception e) {         // todo auto-generated catch block         e.printstacktrace();     }      //create 13 inputnode objects initialized 0.0     (int n = 0; n < 13; n++){         input[n] = new inputnode(0.0);     }     //create 8 hiddennode objects **having problems here**     (int o = 0; o < 8; o++){         hiddennodelayer.add(new hiddennode(input));     }      system.out.println(hiddennodelayer.size() + " hiddennodes created");     //create 1 output node, hidden node     outputnode = new arraylist<hiddennode>(1);     system.out.println(outputnode.size() + " outputnode created"); } 

update: nullpointerexception error

getting error here:

for (int m = 0; m < noofnodes; m++){             input[m] = new inputnode(0.0); //nullpointerexception error         }         system.out.println(input.length);         //create 8 hiddennode objects **having problems here**         int noofhiddennodes = (int)math.floor(2.*noofnodes/3.);         system.out.println(noofhiddennodes);         (int o = 0; o < noofhiddennodes; o++){             hiddennodelayer.add(new hiddennode(input));         } 

found , corrected error

i had initialize input = new inputnode[m] in loop, because there no inputnodes begin with

for (int m = 0; m < noofnodes; m++){             input = new inputnode[m];         }         system.out.println(input.length + "");         //create 8 hiddennode objects **having problems here**         int noofhiddennodes = (int)math.floor(2.*noofnodes/3.);         (int o = 0; o < noofhiddennodes; o++){             hiddennodelayer.add(new hiddennode(input));         }         system.out.println(hiddennodelayer.size() + " hiddennodes created");         //create 1 output node, hidden node         outputnode = new arraylist<hiddennode>(1);         system.out.println(outputnode.size() + " outputnode created");   

do mean this? (by way, hiddennodelayer defined?)

for (int n = 0; n < noofnodes; n++){     input[n] = new inputnode(0.0); } //create 8 hiddennode objects **having problems here** int noofhiddennodes = (int)math.floor(2.*noofnodes/3.); (int o = 0; o < noofhiddennodes; o++){     hiddennodelayer.add(new hiddennode(input)); } 

update: given have defined input arraylist, can push new nodes there in same hiddennodelayer.

private list<inputnode> input = new arraylist<inputnode>(); // input nodes  (int n = 0; n < noofnodes; n++){     input.add(new inputnode(0.0)); } //create 8 hiddennode objects **having problems here** int noofhiddennodes = (int)math.floor(2.*noofnodes/3.); (int o = 0; o < noofhiddennodes; o++){     hiddennodelayer.add(new hiddennode(input)); }