package recta;
public class rect1 {
protected int row;
protected int col;
int a[][] = new int[row][col];
public rect1(int row, int col) {
this.row = row;
this.col = col;
}
void show() {
int i, j;
for (i = 0; i < row; i++) {
for (j = 0; j < col; j++)
System.out.print(a[i][j]);
System.out.println(" ");
}
}
void construct() {
int i, j;
for (i = 0; i < row; i++)
for (j = 0; j < col; j++)
a[i][j] = (int) Math.random();
}
void addtogether() {
int i, j;
int sum = 0;
for (i = 0; i < row; i++)
for (j = 0; j < col; j++)
sum = sum + a[i][j];
System.out.println("所有元素和为:" + sum);
}
}
class square extends rect1{
public square (int row,int col)
{
super(row,col);
}
public void addline()
{int i;
int sum=0;
for(i=0;i<row;i++)
sum=a[i][i]+sum;
System.out.println("主对角线的元素和为:"+sum);
}
public static void main(String args[])
{
square s=new square(6,6);
s.construct();
s.addline();
}
}
为什么the section cannt be launched