找到锯齿状数组的行的平均值

Question

我正在尝试在锯齿状二维数组上找到行的平均值，我已经将数组打印出来，但平均部分打印出错误的平均值。我的代码有什么问题？

//print array
for(int k = 0; k < arr.length; k++) { 
    for(int j = 0; j < arr[k].length; j++) {

        System.out.print(arr[k][j] + " ");             
    }

    System.out.println();
}
          
//average
for (int r = 0; r < arr.length; r++) {
    double sum = 0.0;
    double avg = 0.0;
    for (int c = 0; c < arr[r].length; c++) {
        sum += arr[r][c];  
        avg = sum / i; // i is the columns of the array;
    }
   
    System.out.println("Row " + (row + 1) + " average is: " + avg);
    
}

Answer 1

而不是即时计算平均值，您应该只通过将avg = sum / i; 移动到嵌套循环之外来计算它，否则它会在每次循环时除以不正确的值。也可以改用avg = sum / arr[r].length;，因为我们确切地知道每行有多少列：

    for (int r = 0; r < arr.length; r++){
        double sum = 0.0;
        for (int c = 0; c < arr[r].length; c++){
            sum += arr[r][c];  
        }
        //Calculate the average outside the nested loop using (sum / columns)
        double avg = avg = sum / arr[r].length;
        System.out.println("Row " + (row + 1) + " average is: " + avg);
    }