手把手帶你學習C++的數據類型

#include<iostream>
using namespace std;
int main1()
{
	//整型
	//1.短整型
	short num1 = 10;
	//short num1 = 32768;
	//2.整型
	int num2 = 10;
	//3.長整型
	long num3 = 10;
	//4.長長整型
	long long num4 = 10;
	cout << num1 << endl;
	cout << num2 << endl;
	cout << num3 << endl;
	cout << num4 << endl;
	system("pause");
	return 0;
}

#include<iostream>
using namespace std;
int main2()
{
	//整型：short(2) int(4) long(4) long long(8)
	//可以利用sizeof求出數據類型占用內存大小
	//語法：sizeof（數據類型/變量）
	short num1 = 10;
	cout << "short占用內存空間為：" << sizeof(short) << endl;
	//cout << "short占用內存空間為：" << sizeof(num1) << endl;
	int num2 = 10;
	cout << "int占用內存空間為：" << sizeof(int) << endl;
	//cout << "int占用內存空間為：" << sizeof(num2) << endl;
	long num3 = 10;
	cout << "long占用內存空間為：" << sizeof(long) << endl;
	//cout << "long占用內存空間為：" << sizeof(num3) << endl;
	long long num4 = 10;
	cout << "long long占用內存空間為：" << sizeof(long long) << endl;
	//cout << "long long占用內存空間為：" << sizeof(num4) << endl;
	//整型大小比較
	//short < int <= long <= long long
	system("pause");
	return 0;
}

#include<iostream>
using namespace std;
int main3()
{
	//實型
	//1.單精度 float
	//2.雙精度 double
	//默認情況下，輸出一個小數，會顯示出6位有效數字
	float f1 = 3.1415926f;
	double d1 = 3.1415926;
	cout << "f1 = " << f1 << endl;
	cout << "d1 = " << d1 << endl;
	//float占用4字節內存空間，double占用8字節
	cout << "float占用的內存空間為：" << sizeof(float) << endl;
	cout << "double占用的內存空間為：" << sizeof(double) << endl;
	//科學計數法
	float f2 = 3e2; //3*10^2,300
	cout << "f2 = " << f2 << endl;
	float f3 = 3e-2; //3*0.1^2,0.03
	cout << "f3 = " << f3 << endl;
	system("pause");
	return 0;
}

#include<iostream>
using namespace std;
int main4()
{
	//1.字符型變量創建方式
	char ch = 'a';
	cout << ch << endl;
	//2.字符型變量所占內存大小
	cout << "char字符型變量所占內存為：" << sizeof(char) << endl;
	//3.字符型變量常見錯誤
	//char ch2 = "b"; 創建字符型變量時，要用單引號
	//char ch2 = 'abcdefg'; 創建字符型變量時，單引號內隻能有一個字符
	//4.字符型變量對應ASCII編碼
	//a - 97 A - 65
	cout << (int)ch << endl;
	system("pause");
	return 0;
}

#include<iostream>
using namespace std;
int main5()
{
	//轉義字符
	//換行符\n
	cout << "Hello world" << endl;
	cout << "Hello world\n";
	//反斜杠\\
	cout << "\\" << endl;
	//水平制表符\t
	cout << "aaaa\thelloworld" << endl;
	cout << "aa\thelloworld" << endl;
	cout << "aaaaaa\thelloworld" << endl;
	system("pause");
	return 0;
}

#include<iostream>
#include<string> //用C++風格字符串時，要包含這個頭文件
using namespace std;
int main6()
{
	//1.C風格字符串
	//註意事項1：char字符串名後加[]
	//註意事項2：等號後面要用雙引號，包含起來字符串
	char str[] = "hello world";
	cout << str << endl;
	//2.C++風格字符串
	string str2 = "hello world";
	cout << str2 << endl;
	system("pause");
	return 0;
}

#include<iostream>
using namespace std;
int main7()
{
	//1.創建bool數據類型
	bool flag = true;
	cout << flag << endl;
	flag = false;
	cout << flag << endl;
	//1代表真，0代表假
	//2.查看bool類型所占內存空間
	cout << "bool類型所占內存空間：" << sizeof(bool) << endl;
	system("pause");
	return 0;
}

#include<iostream>
#include<string>
using namespace std;
int main()
{
	//1.整型
	/*int a = 0;
	cout << "請給整型變量a賦值：" << endl;
	cin >> a;
	cout << "整型變量a = " << a << endl;*/
	//2.浮點型
	/*float f = 3.14f;
	cout << "請給浮點型變量f賦值：" << endl;
	cin >> f;
	cout << "浮點型變量f = " << f << endl;*/
	//3.字符型
	/*char ch = 'a';
	cout << "請給字符型變量ch賦值：" << endl;
	cin >> ch;
	cout << "字符型變量ch = " << ch << endl;*/
	//4.字符串型
	/*string str = "hello";
	cout << "請給字符串型變量str賦值：" << endl;
	cin >> str;
	cout << "字符串型變量str = " << str << endl;*/
	//5.佈爾型
	bool flag = false;
	cout << "請給佈爾型變量flag賦值：" << endl;
	cin >> flag;
	cout << "佈爾型變量flag = " << flag << endl;
	system("pause");
	return 0;
}