Question

我需要构造一个接收矩阵作为参数并打印其行的方法。例如，该方法将接收以下矩阵

int[][] matrix = {
    {3, 1, 2, 7, 2, 5, 6, 2},
    {2, 10, 20, 12, 13},
    {3, 7, 12, 15, 18, 4},
    {2, 11, 21, 12, 13}
};

它必须返回

Line 0 : 3 1 2 7 2 5 6 2
Line 1 : 2 10 20 12 13
Line 2 : 3 7 12 15 18 4
Line 3 : 2 11 21 12 13

以下是方法：

public static void displayLines(int[][] matrix){    
    for (int i = 0; i < matrix.length; ++i){
        for (int j = 0; j < matrix[i].length; ++j){ 
            System.out.print("Line nb " + i + " : " + matrix[i][j] + " ");
        }
    }
}

但它没有以我想要的方式打印。它打印得像那样，我试图弄清楚如何解决它。

Line 0 : 3 
Line 0 : 1 
Line 0 : 2 
Line 0 : 7 
Line 0 : 2 
Line 0 : 5 
Line 0 : 6 
Line 0 : 2

// And so on for other lines

Answer 1

您正在为数组的每个元素而不是数组的每一行调用System.out.print。修改如下：

public static void displayLines(int[][] matrix){    
    for (int i = 0; i < matrix.length; ++i){
        System.out.print("Line " + i + " :"); // line header
        for (int j = 0; j < matrix[i].length; ++j){ 
            System.out.print(" " + matrix[i][j]);
        }
        System.out.println(""); // end of line
    }
}

注意如何在每个元素" " + matrix[i][j]之前添加一个空格，以避免尾随空格。

另外请记住，您可以像这样编写第二个for循环

for (int n : matrix[i]) {
    System.out.print(" " + n);
}

Answer 2

如下：

int rowNumber = 0;
for (int[] row : matrix){
    System.out.println("Line " + (rowNumber++) + " : " + Arrays.toString(row));
}

将生成

Line 0 : [3, 1, 2, 7, 2, 5, 6, 2]
Line 1 : [2, 10, 20, 12, 13]
Line 2 : [3, 7, 12, 15, 18, 4]
Line 3 : [2, 11, 21, 12, 13]

Answer 3

使用以下代码

public static void displayLines(int[][] matrix){    
    for (int i = 0; i < matrix.length; ++i){
        System.out.print("Line nb " + i + " : " );
        for (int j = 0; j < matrix[i].length; ++j){ 
            System.out.print(matrix[i][j] + " ");
        }
        System.out.println();
    }
}

Answer 4

public static void displayLines(int[][] matrix) {    
    for (int i = 0; i < matrix.length; ++i) {
        System.out.print("Line " + i + " : ");
        for (int j = 0; j < matrix[i].length; ++j) { 
            System.out.print(matrix[i][j] + " ");
        }
        System.out.println();
    }
}

Answer 5

int[][] matrix = { { 3, 1, 2, 7, 2, 5, 6, 2 }, { 2, 10, 20, 12, 13 },
        { 3, 7, 12, 15, 18, 4 }, { 2, 11, 21, 12, 13 } };
for (int i = 0; i < matrix.length; ++i) {
    System.out.print("Line " + i + " :");
    for (int j = 0; j < matrix[i].length; ++j) {
        System.out.print(matrix[i][j] + "   ");
    }
    System.out.println("");
}

用Java打印矩阵行

5 个答案: