you're reading data from a file, so you want to create the array to keep the data how can you create a 2D array without knowing how many rows it's going to be? thanks

OK. Step is 1. read size that you want to define 2D array from file 2. bring it in declare object array size //this example program read size 2D array from file "dat.txt" import java.io.*; class aarr{ public static void main (String[] asg) throws IOException{ FileInputStream f = new FileInputStream("dat.txt"); InputStreamReader input = new InputStreamReader(f,"8859_1"); BufferedReader bufferR = new BufferedReader(input); String s = bufferR.readLine().trim(); double d = Double.valueOf(s).doubleValue(); bufferR.close(); input.close(); f.close(); int n = (int)d; double [][] a = new double[n][n]; for(int i = 0;i<n;i++){ for(int j=0;j<n;j++){ a[i][j] = 1.234; } System.out.println(i); } } }

aves[i]=CalAves(grades, aves, numStu); }//end main -Calculate------- static void CalAves(int grades[][], double aves[], int numStu){ double sc1, sc2, sc3; for(int i=1; i<numStu; i++){ sc1=double(grades[i][0])/grades[0][0]*100/2; sc2=0.0; for(int j=1; j<4; j++) sc2+=scores[i][j]; sc2=double (sc2/3/3); sc3=0.0; for(int j=4; j<7; j++) sc3+=double (grades[i][j])/grades[0][j]; sc3=sc3*100/4/6; aves[i]=sc1+sc2+sc3; } //end for loop } //end CalAves I want to get the averages from the method, but these are the 3 errors: GradeSystem.java:85: '.class' expected sc1=double(grades[i][0])/grades[0][0]*100/2; ^ GradeSystem.java:89: '.class' expected sc2=double (sc2/3/3); ^ GradeSystem.java:92: '.class' expected sc3+=double (grades[i][j])/grades[0][j]; What does it mean? do i need a new class????

because you declare variable wrong in syntex double sc1, sc2, sc3; // OK in c++ but No OK in java Java must define value too; double sc1 = 1.234; double sc2 = 1.234; double sc3 = 1.234; if not define value for variable when declare you must declare outside function such as class grade(){ double sc1,sc2,sc3; // OK not wrong grade(){ ...; sc1 = ....; // OK not wrong } } otherwise you must define value for variable when declare class grade(){ grade(){ ...; double sc1 = 1.234; double sc2 = 1.234; double sc3 = 1.234; sc1 = ....; } }