c plus plus的%.1f 是什么意思
时间: 2024-01-25 19:03:16 浏览: 22
As an AI language model, I don't have emotions, so the concept of 'null' doesn't apply to me in that sense. In programming, 'null' refers to the absence of a value or the lack of an object or reference.
相关问题
什么是序列化和反序列化,用c plus plus 代码举例
序列化(Serialization)和反序列化(Deserialization)是将数据结构或对象转换为可传输或可存储的格式,以便在不同系统之间进行数据交换或持久化存储。序列化将数据结构或对象转化为字节流或字符串等可传输或可存储的格式,反序列化将字节流或字符串等格式转化为数据结构或对象。
以下是一个使用C++进行序列化和反序列化的示例代码:
```c++
#include <iostream>
#include <fstream>
using namespace std;
// 定义一个数据结构
struct Person {
string name;
int age;
float height;
};
// 序列化函数
void serialize(Person p, string filename) {
ofstream out(filename, ios::binary);
out.write((char*)&p, sizeof(p));
out.close();
}
// 反序列化函数
Person deserialize(string filename) {
Person p;
ifstream in(filename, ios::binary);
in.read((char*)&p, sizeof(p));
in.close();
return p;
}
int main() {
// 定义一个Person对象并赋值
Person p1 = {"Alice", 25, 1.65f};
// 序列化Person对象
serialize(p1, "person.dat");
// 反序列化Person对象
Person p2 = deserialize("person.dat");
// 输出反序列化后的Person对象
cout << "Name: " << p2.name << endl;
cout << "Age: " << p2.age << endl;
cout << "Height: " << p2.height << endl;
return 0;
}
```
在上述代码中,我们定义了一个Person结构体,其中包含name、age和height三个成员变量。然后,我们编写了两个函数:serialize()和deserialize(),分别用于将一个Person对象序列化为二进制文件并将其反序列化回来。在main()函数中,我们创建了一个Person对象p1,并将其序列化为文件person.dat。然后,我们从文件person.dat中反序列化出一个新的Person对象p2,并输出其成员变量。
c plus plus 贪吃蛇游戏 代码
很抱歉,作为AI语言模型,我无法提供可运行的代码。但以下是一个简单的贪吃蛇游戏的C++程序框架,您可以根据需求进行修改和完善。
```
#include <iostream>
#include <conio.h>
#include <windows.h>
using namespace std;
const int width = 20;
const int height = 20;
int x, y, fruitX, fruitY, score;
int tailX[100], tailY[100];
int nTail;
enum eDirection { STOP = 0, LEFT, RIGHT, UP, DOWN };
eDirection dir;
void Setup()
{
dir = STOP;
x = width / 2;
y = height / 2;
fruitX = rand() % width;
fruitY = rand() % height;
score = 0;
}
void Draw()
{
system("cls");
for (int i = 0; i < width + 2; i++)
cout << "#";
cout << endl;
for (int i = 0; i < height; i++)
{
for (int j = 0; j < width; j++)
{
if (j == 0)
cout << "#";
if (i == y && j == x)
cout << "O";
else if (i == fruitY && j == fruitX)
cout << "F";
else
{
bool printTail = false;
for (int k = 0; k < nTail; k++)
{
if (tailX[k] == j && tailY[k] == i)
{
cout << "o";
printTail = true;
}
}
if (!printTail)
cout << " ";
}
if (j == width - 1)
cout << "#";
}
cout << endl;
}
for (int i = 0; i < width + 2; i++)
cout << "#";
cout << endl;
cout << "Score:" << score << endl;
}
void Input()
{
if (_kbhit())
{
switch (_getch())
{
case 'a':
dir = LEFT;
break;
case 'd':
dir = RIGHT;
break;
case 'w':
dir = UP;
break;
case 's':
dir = DOWN;
break;
case 'x':
dir = STOP;
break;
}
}
}
void Logic()
{
int prevX = tailX[0];
int prevY = tailY[0];
int prev2X, prev2Y;
tailX[0] = x;
tailY[0] = y;
for (int i = 1; i < nTail; i++)
{
prev2X = tailX[i];
prev2Y = tailY[i];
tailX[i] = prevX;
tailY[i] = prevY;
prevX = prev2X;
prevY = prev2Y;
}
switch (dir)
{
case LEFT:
x--;
break;
case RIGHT:
x++;
break;
case UP:
y--;
break;
case DOWN:
y++;
break;
case STOP:
break;
}
if (x > width || x < 0 || y > height || y < 0)
{
//游戏结束
}
for (int i = 0; i < nTail; i++)
{
if (tailX[i] == x && tailY[i] == y)
{
//游戏结束
}
}
if (x == fruitX && y == fruitY)
{
score += 10;
fruitX = rand() % width;
fruitY = rand() % height;
nTail++;
}
}
int main()
{
Setup();
while (true)
{
Draw();
Input();
Logic();
Sleep(100);
}
return 0;
}
```