Question

 int sum = 0;   

      for (int i = 0; i < counts.length; i++)      
      {
            sum = sum + counts[i];  //doesnt work says + bad operator  first type int second type int[]

      } 
      return sum;

我认为这样可行，但我无法做些什么才能让它发挥作用？

public static void main(String[] args) {
int[][] counts =
     {
        { 1, 0, 1 },
        { 1, 1, 0 },
        { 0, 0, 1 },
        { 1, 0, 0 },
        { 0, 1, 1 },
        { 0, 1, 1 },
        { 1, 1, 0 }
     };
  int sum = ArrayUtil.rowSum(counts, 5);
  System.out.println(sum);
  System.out.println("Expected: 2");

  int[][] magicSquare = {
     { 16, 3, 2, 13 },
     { 5, 10, 11, 8 },
     { 9, 6, 7, 12 },
     { 4, 15, 14, 1 },
  };

  for (int row = 0; row <= 3; row++)
  {
     System.out.println(ArrayUtil.rowSum(magicSquare, row));
     System.out.println("Expected: 34");
  }
}
  public static int rowSum(int[][] counts, int row) 
  {   
      int sum = 0;   

      for (int i = 0; i < counts.length; i++)      
      {
            sum = sum + counts[i];    

      } 
      return sum;
  }

添加了我的完整代码。非常感谢anyhelp。是不行，因为count [i]是2d数组的一部分？

Answer 1

counts是一个多维数组，因此您需要迭代内部数组中包含的值以获取sum。使用可能类似的for-each loops，

int sum = 0;
for (int[] array : counts) {  // <-- for each array in counts
    for (int value : array) { // <-- for each value in the array
        sum += value;         // <-- add the value to the sum
    }
}

将相同的循环结构应用于rowSum，我们可能会得到

public static int rowSum(int[][] counts, int row) {   
    int sum = 0;   
    for (int value : counts[row]) {
        sum += value;
    } 
    return sum;
}

或使用Java 8+ IntStream之类的

public static int rowSum(int[][] counts, int row) {
    return IntStream.of(counts[row]).sum();
}

Answer 2

如果您尝试对2D数组的单行求和，则您的方法应如下所示：

public static int rowSum(int[][] counts, int row) {
    int sum = 0;
    for (int count : counts[row]) {
        sum += count;
    }
    return sum;
}

Answer 3

counts是int的二维数组（即int[][]）您无法将int[]添加到int。

如果要对counts的值求和，请考虑以下代码：

int sum = 0;
for(int i = 0; i < counts.length; i++) {
    for(int j = 0; j < counts[i].length; j++) {
        sum += counts[i][j];
    }
}

Answer 4

我用递归做了这个，因为每个人都发布了他们自己的答案，所以我做了这种递归方式。

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希望您的答案有用。

用int []添加int

4 个答案: