[C/JAVA]二维数组

C

//计算每个学生成绩，并求和，计算平均数
#include <stdio.h>
void main() {
    int scores[][4] = { //不足4个元素，用0补充
        {100, 99, 98, 99,},
        {78, 86, 77,},
        {43, 56},
        {}
    };
    int sum = 0, i, j;
    for (i = 0; i < 4; ++i, sum = 0) {
        for (j = 0; j < 4; ++j) {
            printf("%4d", scores[i][j]);
            sum += scores[i][j];
        }
        printf(" sum = %4d average = %4.1f
", sum, sum / (j+.0));
    }
}

结果:

 100  99  98  99 sum =  396 average = 99.0
  78  86  77   0 sum =  241 average = 60.2
  43  56   0   0 sum =   99 average = 24.8
   0   0   0   0 sum =    0 average =  0.0

JAVA

public class TwoDimenArray {
    public static void main(String[] args) {
        int[][] scores= new int[][] { //ragged array，不会自动用0填充
            new int[] {89, 90, 100, 94, 99},
            new int[] {56, 60, 61},
            new int[] {103, }
        };

        //或者
        // int[][] scores= new int[3][];
        // scores[0] = new int[] {89, 90, 100, 97};
        // scores[1] = new int[] {56, 60};
        // scores[2] = new int[] {103, 99, 101};

        int sum = 0;
        int i, j;
        for ( i = 0;i < scores.length; ++i, sum = 0 ) { //计算新一组和，把sum调成0
            for ( j = 0; j < scores[i].length; ++j ) {
                System.out.printf( "%4d", scores[i][j] );
                sum += scores[i][j];
            }
            System.out.print("  Sum = " + sum + " Average = " + sum / (j + .0));
            System.out.println();
        }
    }
}

运行结果

  89  90 100  94  99  Sum = 472 Average = 94.4
  56  60  61  Sum = 177 Average = 59.0
 103  Sum = 103 Average = 103.0