如何在java中对二维数组的列求和 [英] how to sum the columns of a 2 dimensional array in java

问题描述

好的，我正在尝试添加二维数组的列的总和，但到目前为止，我能够添加行的总和，但不能添加其他 3 列.有人可以告诉我我做错了什么吗?

ok, I'm trying to add the the sum of the columns of a two dimensional array but so far i was able to add the total of the sum of the rows but Not the other 3 columns. can someone please show me what I'm doing wrong?

    public static void main(String[] args) throws IOException
{
    // TODO code application logic here
    File election = new File("voting_2008.txt");
    Scanner sc = new Scanner(election);

    String[] states = new String[51];
    int[][]votes = new int[51][3];


    for (int s=0; s < 51; s++)
    {
        states[s] = sc.nextLine();
    }

    for(int c=0; c < 3; c++)
    {
        for(int s=0; s < 51; s++)
        {
            votes[s][c] = sc.nextInt();

        }

    }
    Formatter fmt = new Formatter();
    fmt.format("%20s%12s%12s%12s%21s", "State", "Obama", "McCain", "Other", "Total by state");
    System.out.println(fmt);
    int TotalSum; 
    TotalSum = 0;
    for (int s=0; s < 51; s++)
    {
       fmt = new Formatter();
       fmt.format("%20s", states[s]);
       System.out.print(fmt);
       for(int c=0; c < 3; c++)
       {
           fmt = new Formatter();
           fmt.format("%12d", votes[s][c]);
           System.out.print(fmt);

       }


           int sum =0;
           for (int col=0; col < votes[s].length; col++)
           {
              sum = sum + votes[s][col];

           }

           TotalSum += sum;
           fmt = new Formatter();
            fmt.format("%21d", sum);
            System.out.print(fmt); 



       System.out.println();

    }
    Formatter fmt2 = new Formatter();
    fmt2.format("%20s%12s%12s%12s%21s", "Total", "", "", "", TotalSum);
    System.out.print( fmt2 );
}

}

推荐答案

几个简单的更改即可解决您的问题:

Couple of simple changes to fix your issue:

1> 将前两个 for 循环合并为:

1> Merge the first two for loops as:

    for (int s=0; s < 2; s++){
        states[s] = sc.next();
        for(int c=0; c < 3; c++) {
            votes[s][c] = sc.nextInt();
        }
    }

1. 在 TotalSum 旁边定义一个新的 colSum[]，如下所示:

1. Define a new colSum[] next to TotalSum as below:

int TotalSum = 0;
int colSum[] = new int[]{0,0,0};

更新投票打印循环以进行列总和:

Update vote printing for loop to do the column sum as well:

   for(int c=0; c < 3; c++) {
       colSum[c]+=votes[s][c]; // <-- new line to do the column sum
       fmt = new Formatter();
       fmt.format("%12d", votes[s][c]);
       System.out.print(fmt);
   }

将最后一行中的列总和打印为:

Print the columns sum in last line as :

    fmt2.format("%20s%12s%12s%12s%21s", "Total", colSum[0], colSum[1], colSum[2], TotalSum);
    System.out.print( fmt2 );

希望这有帮助！！

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