class A{
int i, j;
A(int m, int n){
i = m;
j = n;
}
void showij(){
System.out.println("i and j:" + i + '\t' + j);
}
}class B extends A {
int k;
B(int m, int n)
{
i = m;
j = n;
}
void showk(){
System.out.println("k:" + k);
}
}
int i, j;
A(int m, int n){
i = m;
j = n;
}
void showij(){
System.out.println("i and j:" + i + '\t' + j);
}
}class B extends A {
int k;
B(int m, int n)
{
i = m;
j = n;
}
void showk(){
System.out.println("k:" + k);
}
}
int i, j;
A(int m, int n){
i = m;
j = n;
}
void showij(){
System.out.println("i and j:" + i + '\t' + j);
}
}class B extends A {
int k;
B(int m, int n)
{
super(m,n);
}
void showk(){
System.out.println("k:" + k);
}
}因为A没有默认构造函数 所显式的调用父类的构造函数或者定一个默认构造函数class A{
int i, j;
A(int m, int n){
i = m;
j = n;
}
A(){
}
void showij(){
System.out.println("i and j:" + i + '\t' + j);
}
}class B extends A {
int k;
B(int m, int n)
{
i = m;
j = n;
}
void showk(){
System.out.println("k:" + k);
}
}