How to print an array that was inputted from Scanner?

Question

So I have an array and trying to print what was input to the scanner. I'm trying to print the matrix that was input. Heres the code, what am I doing wrong here? I tried to print just graph, doesn't work.

/** Accept number of vertices **/
    System.out.println("Enter number of vertices\n");
    int V = input.nextInt();

    /** get graph **/
    System.out.println("\nEnter matrix\n");
    int[][] graph = new int[V][V];
    for (int i = 0; i < V; i++)
        for (int j = 0; j < V; j++)
            graph[i][j] = input.nextInt();
            System.out.print(graph);

are you purposely trying to print the graph after each input from the user? or are you trying to print it out once when all the inputs have been received? — RAZ_Muh_Taz, Oct 31 '16 at 20:54
@RAZ_Muh_Taz He's just printing it at the end. Although the `System.out.println(graph);` is indented, it isn't part of the for loops because the for loops have no curly braces. — Asaph, Oct 31 '16 at 20:56
oh ok, that's right. the indentation and no curly braces were messing with my head... thanks for the clarification @Asaph — RAZ_Muh_Taz, Oct 31 '16 at 20:58

Asaph · Answer 1 · 2016-10-31T20:57:34.220

0

You can print the contents of an array using the Arrays.toString() method but it doesn't work for multidimensional arrays, so for a 2 dimensional array, you'll need to loop through the elements in the first dimension. Like this:

for (int[] g : graph) {
    System.out.println(Arrays.toString(g));
}

edited Oct 31 '16 at 20:57

answered Oct 31 '16 at 20:50

Asaph

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score 0 · Answer 2 · edited May 23 '17 at 12:24

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Printing arrays by simply passing it into System.out.print will print the array's hashcode. See this.

What you want to do is: System.out.println(Arrays.deepToString(graph));

Arrays.toString(...) will work for single dimensional arrays.

Arrays.deepToString(...) will work for more complex arrays.

edited May 23 '17 at 12:24

Community

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answered Oct 31 '16 at 20:54

pushkin

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score 0 · Answer 3 · answered Oct 31 '16 at 20:56

Because when you try to print graph, you are actually printing a reference to an array object (If I am correct).

Also, for variables (like "V") you should use small caps

Instead of printing a graph, do this:

 for (int i = 0; i < V; i++) {
            for (int j = 0; j < V; j++) {
                System.out.print(graph[i][j]);
            }
            System.out.println();
        }

How to print an array that was inputted from Scanner?

3 Answers3