一些C++的小程序（一）

输出hello word

#include 
using namespace std;


int main()
{
	cout << "hello，word\n";
    return 0;
}

查找int的空间大小

#include 
using namespace std;

int main()
{
	cout << "The size of an int is :\t\t" << sizeof(int) << "bytes.\n";
    return 0;
}

定义枚举类型，输出比赛结果

#include 
using namespace std;
enum GameResult {WIN,LOSE,TIE,CANCEL};
int main()
{
	GameResult result;
	enum GameResult omit = CANCEL;
	for (int count = WIN; count <= CANCEL; count++) {
		result = GameResult(count);
		if (result == omit)
			cout << "The game was cancelled" << endl;
		else {
			cout << "The game was played";
			if (result == WIN) cout << "and we won";
			if (result == LOSE) cout << "and we lost";
			cout << endl;
		}
	}
    return 0;
}

使用do-while语句，求自然数1-10之和

#include 
using namespace std;
int main()
{
	int i = 1, sum = 0;
	do { sum += 1;
	i++;
	} while (i <= 10);
	cout << "sum=" << sum << endl;
    return 0;
}

//计算圆形，正方形，矩形的面积，运行时先提示用户选择图形类型，
//然后对图形要求用户输入半径值，对长方形要求用户输入长和宽的值，
//对正方形要求用户输入边长的值，计算面积的值然后显示出来。

#include 
using namespace std;
const float PI = 3.1416;

int main()
{
	int iType;
	float radius, a, b, area;
	cout << "图形的类型为？（1-圆形 2-正方形 3-圆）:";
	cin >> iType;
	switch(iType)
	{
	case 1:
		cout << "圆的半径：";
		cin >> radius;
		area = PI*radius*radius;
		cout << "面积为：" << area << endl;
		break;
	case 2:
		cout << "矩形的长为：";
		cin >> a; 
		cout << "矩形的宽为：";
		cin >> b;
		area = a*b;
		cout << "面积为：" << area << endl;
		break;
	case 3:
		cout << "正方形的半径：";
		cin >> a;
		area = a*a;
		cout << "面积为：" << area << endl;
		break;
	default:
		cout << "不是合法输入值"<

//声明一个表示时间的结构体
//可以精确表示年月日小时分秒
//提示用户输入然后完全显示（利用struct结构体)

#include "iostream"
using namespace std;
struct MytimeStruce
{
	unsigned int year;
	unsigned int month;
	unsigned int day;
	unsigned int hour;
	unsigned int min;
	unsigned int sec;
};

int main()
{
	MytimeStruce mytime = { 2017,11,22,18,45,58 };
	cout << "please input year:" << endl;
	cin >> mytime.year;
	cout << "please input month:" << endl;
	cin >> mytime.month;
	cout << "please input day:" << endl;
	cin >> mytime.day;
	cout << "please input hour:" << endl;
	cin >> mytime.hour;
	cout << "please input min:" << endl;
	cin >> mytime.min;
	cout << "please input sec:" << endl;
	cin >> mytime.sec;
	cout << "the time is set to:" << mytime.year << "/";
	cout << mytime.month << "/";
	cout << mytime.day << " ";
	cout << mytime.hour << ":";
	cout << mytime.min << ":";
	cout << mytime.sec << endl;
    return 0;
}

//利用函数计算x的n次方

#include "iostream"
using namespace std;
double power(double x, int n) {
	double val = 1.0;
	while (n--)
		val *= x;
	return val;
}
int main()
{
	double pow;
	pow = power(5, 2);
	cout << "5 to the power 2 is " << pow << endl;
    return 0;
}

//函数的嵌套
//输入两个数，求两个数的平方和

#include "iostream"
using namespace std;
int fun2(int m) {
	return m*m;
}
int fun1(int x, int y) {
	return fun2(x) + fun2(y);
}
int main()
{
	int a, b;
	cout << "Please enter two integers(a and b):";
	cin >> a >> b;
	cout << "The sum of square of a and b :" << fun1(a, b) << endl;
    return 0;
}

//利用的函数的引用

//输入两个整数交换后输出

#include "iostream"
using namespace std;
void swap(int &a, int &b) {
	int t = a;
	a = b;
	b = t;
}

int main()
{
	int x = 5, y = 10;
	cout << "x=" << x << "y=" << y <#include "iostream"
using namespace std;
const double PI = 3.14159265358979;
inline double calArea(double radius) {
	return PI*radius*radius;
}

int main()
{
	double r = 3.0;
	double area = calArea(r);
	cout << area << endl;
    return 0;
}

//使用debug的 step into功能追踪到函数内部
//编写函数float Convert（float F）参数和返回值为float类型
//实现算法：C=(F-32)*5/9

#include "iostream"
using namespace std;
float Convert(float F){
	float C;
	C = (F - 32) * 5 / 9;
	return C;
}

int main()
{
	float F;
	cout << "Please input the temperature in fahrenheit:\n";
	cin >> F;
	cout << "Conver the temperature in celsius:\n";
	cout << Convert(F);
    return 0;
}