資料類型
字元型
# include <iostream>
using namespace std;
int main(){
char ch = 'a';
cout << ch << endl;
//char ch2 = "a";
//char ch1 = 'abcde';
cout << "字元變量所占的記憶體空間是："<<sizeof(ch)<<endl;
cout << (int)ch<<endl;
char ch3 = 'A';
cout << (int)ch3 << endl;
return 0;
}
/*
a
字元變量所占的記憶體空間是：1
97
65
*/
轉義字元
# include <iostream>
using namespace std;
int main(void){
//轉義字元
//1.換行符\n
cout<<"hello world"<<endl;
cout <<"hello world\n";
//2.反斜杠
cout<<"\\hello world\n";
//3.橫向制表符\t(占8個空格，兩個間隔的空格數是：8減去前面變量所占的空格數)
cout << "abcde\t12345\n";
cout << "abc\t3456\n" ;
cout << "a\t12344567\n";
cout <<"abcedfgh\t123\n";
return 0;
}
/*
hello world
hello world
\hello world
abcde 12345
abc 3456
a 12344567
abcedfgh 123
*/
字元串
#include <iostream>
using namespace std;
#include <string>//string頭檔案
int main(){
//1.C風格的字元串
char str[] = "不積跬步無以至千裡";
cout << str << endl;
//2.C++風格的字元串
string str1 = "一口吃不成一個胖子";//string 小寫
cout << str1 << endl;
return 0;
}
/*
不積跬步無以至千裡
一口吃不成一個胖子
*/
布爾類型
# include <iostream>
using namespace std;
int main(){
bool flag = true;
cout << flag << endl;
flag = false;
cout << flag << endl;
//bool占一個位元組
cout << "bool 所占的記憶體空間是："<< sizeof(bool) << endl;
return 0;
}
/*
1
0
bool 所占的記憶體空間是：1
*/
資料輸入
# include <iostream>
using namespace std;
# include <string>
int main(){
//1.鍵盤輸入int類型
int i = 10;
cout << "請輸入int類型的變量i的值" << endl;
cin >> i ;
cout << "int 類型的值a = " << i << endl;
return 0;
}
# include <iostream>
using namespace std;
# include <string>
int main(){
//2.鍵盤輸入float類型
float f = 23.4f;
cout << "請輸入float類型變量的值:"<< endl;
cin >> f;
cout << "float 類型變量的值是："<< f << endl;
return 0;
}
# include <iostream>
using namespace std;
# include <string>
int main(){
//3.鍵盤輸入char類型
char ch = 'H';
cout << "請輸入char 類型變量的值"<< endl;
cin >> ch;
cout << "ch = "<< ch <<endl;
return 0;
}
/*
請輸入char 類型變量的值
a
ch = a
*/
# include <iostream>
using namespace std;
# include <string>
int main(){
//4.鍵盤輸入string類型
string str = "日積月累";
cout << "請輸入字元串的值"<< endl;
cin >> str;
cout << "str = " << str << endl;
return 0;
}
/*
請輸入字元串的值
你好
str = 你好
*/
# include <iostream>
using namespace std;
# include <string>
int main(){
//5.鍵盤輸入bool類型
bool flag = false;
cout << "請輸入布爾類型的變量flag的值" << endl;
cin >> flag;
//flag的值隻有0,1,0表示假，1表示真
cout << "flag = "<< flag << endl;
return 0;
}
/*
請輸入布爾類型的變量flag的值
23
flag = 1
運算符
算術運算符
# include <iostream>
using namespace std;
int main(){
int a = 10;
int b = 30;
cout << "a+b=" << a+b << endl;
cout << "a-b=" << a-b << endl;
cout << "a*b=" << a*b << endl;
cout << "a/b=" << a/b << endl;//兩個整數相除得到整數
cout << "2.4/2=" << 2.4/2 << endl;
//cout << "a/0=" << a/0;//0不能作為除數
cout << "a%b=" << a%b << endl;
//cout << "2.4 % 1.2=" << 2.4 % 1.2 << endl;//隻能對整數取餘 (模)
//前自增和前自減
int x = 10;
++x;
int y = 20;
--y;
cout << "x = "<< x << endl;
cout << "y =" << y << endl;
//後自增和後自減
int m = 11;
m++;
int n = 12;
n-- ;
cout << "m = " << m << endl;
cout << "n = " << n << endl;
//前自增（減）和後自增（減）的差別
int k = 10;
int p = ++k * 10;
cout <<"k = " << k << ",l = " << p << endl;
//前自增（減）：先自增（減），再給表達式指派
int s = 11;
int h = s--%3;
cout << "s = "<< s << ",h = " << h << endl;
return 0;
}
/*
a+b=40
a-b=-20
a*b=300
a/b=0
2.4/2=1.2
a%b=10
x = 11
y =19
m = 12
n = 11
k = 11,l = 110
s = 10,h = 2
*/
指派運算符
# include <iostream>
using namespace std;
int main(){
//指派運算符
// =
int a = 10;
a = 100;
cout << a << endl;
// +=
a = 100;
a += 100;
cout << a << endl;
// -=
a = 100;
a -= 50;
cout << a << endl;
// *=
a = 100;
a *= 2;
cout << a << endl;
// /=
a = 100;
a /= 10;
cout << a << endl;
// %=
a = 100;
a %= 30;
cout << a << endl;
}
/*
100
200
50
200
10
10
*/
比較運算符
# include <iostream>
using namespace std;
int main(void)
{
//比較運算符
int a = 10;
int b = 30;
// ==
cout << (a == b) << endl;
// !=
cout << (a!= b) << endl;
// >
cout << (a > b) << endl;
// <
cout << (a < b) << endl;
// >=
cout << (a >= b) << endl;
// <=
cout << (a <= b) << endl;
return 0;
}
/*
0
1
0
1
0
1
*/
邏輯運算符
# include <iostream>
using namespace std;
int main(){
//邏輯運算符
// !
int a = 10;
int b = 0;
cout << (!a) << endl;
cout << (!b) << endl;
// &&
cout << (10 && 10) << endl;
cout << (0 && 20) << endl;
cout << (0 && 0) << endl;
// ||
cout << (10 || 0) << endl;
cout << (10 || 10) << endl;
cout << (0 || 0) << endl;
return 0;
}
/*
0
1
1
0
0
1
1
0
*/
程式流程結構
選擇結構-if語句
# include <iostream>
using namespace std;
int main(){
//if 單行判斷
int age = 0;
cout << "請輸入你的年齡："<< endl;
cin >> age;
cout << "您輸入的年齡是：" << age << endl;
//如果年齡大于20，已經成年
if (age > 18)
{
cout << "您已經成年" << endl;
}
return 0;
}
/*
if單行判斷
請輸入你的年齡：
18
您輸入的年齡是：18
請輸入你的年齡：
20
您輸入的年齡是：20
您已經成年
*/
# include <iostream>
using namespace std;
int main(){
//if判斷
int age = 0;
cout << "請輸入你的年齡："<< endl;
cin >> age;
cout << "您輸入的年齡是：" << age << endl;
//如果年齡大于20，已經成年
if (age > 18)
{
cout << "您已經成年" << endl;
}
else
{
cout << "您還沒有成年" << endl;
}
return 0;
}
/*
請輸入你的年齡：
16
您輸入的年齡是：16
您還沒有成年
*/
# include <iostream>
using namespace std;
int main(){
//if判斷
int age = 0;
cout << "請輸入你的年齡："<< endl;
cin >> age;
cout << "您輸入的年齡是：" << age << endl;
//如果年齡大于20，已經成年
if (age > 18)
{
cout << "您已經成年" << endl;
}
else if (age > 15)
{
cout << "正在上國中" << endl;
}
else if (age > 7)
{
cout << "正在上國小" << endl;
}
else if (age > 5)
{
cout << "在上幼稚園" << endl;
}
else
{
cout << "還沒有上學" << endl;
}
return 0;
}
/*
請輸入你的年齡：
16
您輸入的年齡是：16
正在上國中
請輸入你的年齡：
10
您輸入的年齡是：10
正在上國小
*/
選擇結構-嵌套if
# include <iostream>
using namespace std;
int main()
{
//找出三個人中身高最高的人；
int a = 0;
int b = 0;
int c = 0;
cout << "請輸入第一個人的身高："<< endl;
cin >> a;
cout << "請輸入第二個人的身高："<< endl;
cin >> b;
cout << "請輸入第三個人的身高：" << endl;
cin >> c;
cout << "你輸入的三個人的身高分别是："<< a << "," << b << "," << c << endl;
if ( a > b)
{
if (a > c)
{
cout << "第一個人最高" << a << endl;
}
else
{
cout << "第三個人最高 " << c << endl;
}
}
else
{
if (b > c)
{
cout << "第二個人最高" << b << endl;
}
else
{
cout << "第三個人最高" << c << endl;
}
}
cout << "三目運算符" << endl;
int temp = 0;
int max = 0;
temp = (a > b)? a : b;
max = (temp > c)? temp : c;
cout << "max = " << max << endl;
return 0;
}
/*
請輸入第一個人的身高：
189
請輸入第二個人的身高：
190
請輸入第三個人的身高：
188
你輸入的三個人的身高分别是：189,190,188
第二個人最高190
三目運算符
max = 190
*/
選擇結構-三目運算符
# include <iostream>
using namespace std;
int main()
{
//三目運算符傳回的是變量
int a = 10;
int b = 3;
int c = 0;
c = (a > b? a : b); //把b 的值賦給a
cout << "c = " << c << endl;//10
//(a > b? a:b)傳回的是a
( a > b? a:b) = 100;//把100的值賦給a;
cout << "a = " << a << ",b = " << b << endl;//a = 100,b = 3
(a < b?b:a) = 30;
cout << "a = " << a << ",b = " << b << endl;//a = 30,b = 3
}
選擇結構-switch
# include <iostream>
using namespace std;
int main()
{
int month;
cout << "請輸入目前的月份"<< endl;
cin >> month;
cout <<"您輸入的月份是" << month << endl;
switch (month)
{
case 12:
cout << "冬天" << endl;
break;
case 1:
cout << "冬天" << endl;
break;
case 2:
cout << "冬天" << endl;
break;
case 3:
cout << "春天" << endl;
break;
case 4:
cout << "春天" << endl;
break;
case 5:
cout << "春天" << endl;
break;
case 6:
cout << "夏天" << endl;
break;
case 7:
cout << "夏天" << endl;
break;
case 8:
cout << "夏天" << endl;
break;
case 9:
cout << "秋天" << endl;
break;
case 10:
cout << "秋天" << endl;
break;
case 11:
cout << "秋天" << endl;
break;
default:
cout << "您的輸入有誤"<<endl;
break;
}
return 0;
}
/*
請輸入目前的月份
12
您輸入的月份是12
冬天
*/
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