After using the treeset custom deduplicated comparator in java, an element was repeatedly added and then deleted, but the element could not be deleted.
public static void main(String[] args) {
TreeSet ts = new TreeSet(new Comparator() {
@Override
public int compare(Integer o1, Integer o2) {
return o1==o2?0:1;
}
});
ts.add(3);
ts.add(3);
ts.add(3);
ts.add(1);
ts.add(2);
ts.remove(3);
for(int i:ts){
System.out.println(i);
}
}
Running ...
问题遇到的现象和发生背景
c++ find_if()函数查找自定义类型时返回的结束迭代器在for循环中不能结束循环
用代码块功能插入代码,请勿粘贴截图
// 对于基本数据类型没有问题
for (vector::iterator it = v1.begin(); it != v1.end(); it++)
{
it = find_if(it, v1.end(), fi nd2X); // 返回符合的迭代器(2的倍数)
if (it != v1.end())
{
cout ...
Define class Circle, including radius r, attribute R to determine the value of r is reasonable(r> 0). Including the method of calculating the Area of the Circle Area().
Derive Cylinder class from circle class, and add the high h attribute H of the cylinder to judge the value rationality of h(h > 0). Create a Cylinder object and output the ground radius, height, and volume of the object.
...
constructor error showing class redefined
As shown here, write A class in a header file(Point.h) and write the constructor
.
class CPoint
{
public:
CPoint(void)
{
Lx = 16. 012;
Ly = 79.963;
Rx = -73.93;
Ry = 78.705;
X = 5083.205;
Y = 5852.099;
Z = 527.925;
flag = true;
};
~CPoint(void) {};
Contains
i n the B header file
#pragma once
#include "Point.h"
gives an error indicating that the class has been redefined
Even with #pragma once, doesn't solve the problem, wonder what t...