Merge branch 'learning' into 'main'

Merge initial repository of learning

See merge request clark/study!1

01.Basic/HelloWorld.cpp

+#include <iostream>
+using namespace std;
+
+// main() 是程序开始执行的地方
+
+/* 这是注释 */
+
+/* C++ 注释也可以
+ * 跨行
+ */
+
+int main(){
+    cout << "Hello World"; // 输出 Hello World
+    return 0; 
+} 
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01.Basic/VariableBasicType.cpp

+#include <iostream>
+#include <stdio.h>
+using namespace std;
+
+// main() 是程序开始执行的地方
+
+int main(){
+
+    // 起始行
+    cout << "---------------------------------" << endl;
+
+    cout << "Size of char      : " << sizeof(char) << endl;
+    cout << "Size of int       : " << sizeof(int) << endl;
+    cout << "Size of short int : " << sizeof(short int) << endl;
+    cout << "Size of long int  : " << sizeof(long int) << endl;
+    cout << "Size of float     : " << sizeof(float) << endl;
+    cout << "Size of double    : " << sizeof(double) << endl;
+    cout << "Size of wchar_t   : " << sizeof(wchar_t) << endl;
+
+    cout << "---------------------------------" << endl;
+
+    /********************************************
+     * 布尔型 1 个字节
+     * 0 或者 1
+     *******************************************/
+    bool true_or_false;
+
+    true_or_false = true;
+    if (true_or_false) {
+        // Output 01
+        cout << "Output 01 | True (" << true_or_false << ")" << endl;
+    }
+
+    true_or_false = false;
+    if (!true_or_false) {
+        // Output 02
+        cout << "Output 02 | False (" << true_or_false << ")" << endl;
+    }
+
+    /********************************************
+     * 字符型 1 个字节
+     * char          : -128 到 127 或者 0 到 255
+     * unsigned char : 0 到 255
+     *******************************************/
+    char char_min, char_max, char_A, char_overflow;
+    char_min = int(0);
+    char_max = int(255);
+    char_A = int(65);
+    // char_overflow = int(256); // 将会产生数值溢出错误
+
+    // Output 03
+    cout << "Output 03 | Char Min is " << char_min << " (" << int(char_min) << ")" << endl;
+    cout << "Output 04 | Char Max is " << char_max << " (" << int(char_max) << ")" << endl;
+    cout << "Output 05 | Char A is " << char_A << " (" << int(char_A) << ")" << endl;
+    // cout << "Output 05 | Char Overflow is " << char_overflow << " (" << int(char_overflow) << ")" << endl;
+
+    /********************************************
+     * 自定义类型
+     * 使用 typedef 为一个已有的类型取一个新的名字
+     *******************************************/
+    typedef int feet;
+    feet distance;
+    distance = 123;
+    cout << "Output 06 | distance is " << distance << endl;
+
+    /********************************************
+     * 枚举类型
+     *******************************************/
+    enum color { red, green, blue } c;
+    c = green;
+    cout << "Output 07 | Enum c is " << c << endl;
+
+    // 结束行
+    cout << "---------------------------------" << endl;
+
+    return 0; 
+} 
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