添加名称名称空间和常量作用域

base/CMakeLists.txt

@@ -38,4 +38,11 @@ add_executable(twotemps template/twotemps.cpp)
 add_executable(twotemp template/twotemp.cpp)
 add_executable(temptempover template/temptempover.cpp)
 add_executable(choices template/choices.cpp)
-add_executable(testtemplate template/testtemplate.cpp)
+add_executable(testtemplate template/testtemplate.cpp)
+add_executable(file1 namespacetest/file1.cpp)
+add_executable(file2 namespacetest/file2.cpp)
+add_executable(test10001 namespacetest/test10001.cpp)
+add_executable(auto namespacetest/auto.cpp)
+add_executable(external namespacetest/external.cpp)
+add_executable(support namespacetest/support.cpp)
+add_executable(ststic namespacetest/ststic.cpp)

base/namespacetest/auto.cpp

@@ -0,0 +1,36 @@
+//
+// Created by zhuyijun on 2021/8/16.
+//
+
+#include <iostream>
+
+using namespace std;
+
+void oil(int x);
+/**
+ * 变量的作用域
+ * @return
+ */
+int main() {
+    using namespace std;
+    int texas = 31;
+    int year = 2011;
+    cout << "In main(), texas = " << texas << ", &texas = " << &texas << endl;
+    oil(texas);
+    cout << " In main(), texas = " << texas << " , &texas = " << &texas << endl;
+    cout << "In main(), year = " << year << " , &year = " << &year << endl;
+    return 0;
+}
+
+void oil(int x) {
+    using namespace std;
+    int texas = 5;
+    cout << "In oil(), texas = " << texas << ", &texas = " << &texas << endl;
+    cout << "In oil(), x = " << x << ", &x = " << &x << endl;
+    {
+        int texas = 113;
+        cout << "In block, texas = " << texas<< ", &texas = " << &texas << endl;
+        cout << "In block,x = " << x << ", &x = " << &x << endl;
+    }
+    cout << "Post-block texas = " << texas << ", &texas = " << &texas << endl;
+}

base/namespacetest/coordin.h

@@ -14,6 +14,6 @@ struct rect{
     double y;
 };
 
-polarrect_to_polar(rect xypos);
+polar rect_to_polar(rect xypos);
 void show_polar(polar dapos);
 #endif //BASE_COORDIN_H

base/namespacetest/external.cpp

@@ -0,0 +1,36 @@
+//
+// Created by zhuyijun on 2021/8/16.
+//
+
+#include <iostream>
+
+using namespace std;
+
+double warming = 0.3;
+
+void update(double dt);
+
+void local();
+
+int main() {
+    cout << "Global warming is " << warming << "degrees. \n";
+    update(0.1);
+    cout << "Global warming is " << warming << "degrees. \n";
+    local();
+    cout << "Global warming is " << warming << "degrees. \n";
+    return 0;
+}
+
+void update(double dt) {
+    extern double warming;
+    warming += dt;
+    cout << "Updating global warming to " << warming;
+    cout << "degrees. \n";
+}
+
+void local() {
+    double warming = 0.8;
+    cout << "Local warming = " << warming << " degrees.\n";
+    cout << "But global warming = " << ::warming;
+    cout << " degrees.\n";
+}

base/namespacetest/file1.cpp

@@ -9,6 +9,15 @@ using namespace std;
 
 int main() {
 
+    rect rplace;
+    polar pplace;
 
+    cout << "Enter the x and y values: ";
+    while (cin >> rplace.x >> rplace.y) {
+        pplace = rect_to_polar(rplace);
+        show_polar(pplace);
+        cout << "Next two numbers (q to quit)";
+    }
+    cout << "Bye! \n";
     return 0;
 }

base/namespacetest/file2.cpp

@@ -0,0 +1,24 @@
+//
+// Created by zhuyijun on 2021/8/16.
+//
+
+#include "coordin.h"
+#include <iostream>
+#include <cmath>
+
+polar rect_to_polar(rect xypos) {
+    using namespace std;
+    polar answer;
+
+    answer.distance = sqrt(xypos.x * xypos.x + xypos.y * xypos.y);
+    answer.angle = atan2(xypos.y, xypos.x);
+    return answer;
+}
+
+void show_polar(polar dapos) {
+    using namespace std;
+    const double Rad_to_deg = 57.29577951;
+    cout << "distance = " << dapos.distance;
+    cout << " , angle = " << dapos.angle * Rad_to_deg;
+    cout << " degrees \n";
+}

base/namespacetest/ststic.cpp

@@ -0,0 +1,40 @@
+//
+// Created by zhuyijun on 2021/8/16.
+//
+
+#include <iostream>
+
+using namespace std;
+const int ArSize = 10;
+
+void strcount(const char *str);
+
+int main() {
+
+    char input[ArSize];
+    char next;
+
+    cout << " Enter a line:\n";
+    cin.get(input, ArSize);
+    while (cin) {
+        cin.get(next);
+        while (next != '\n')
+            cin.get(next);
+        strcount(input);
+        cout << "Enter next line (empty line to quit):\n";
+        cin.get(input, ArSize);
+    }
+    cout << "Bye\n";
+    return 0;
+}
+
+void strcount(const char *str) {
+    static int total = 0;
+    int count = 0;
+    cout << "\"" << str << "\" contains ";
+    while (*str++)
+        count++;
+    total += count;
+    cout  << " characters \n";
+    cout << total << " characters total\n";
+}

base/namespacetest/support.cpp

@@ -0,0 +1,30 @@
+//
+// Created by zhuyijun on 2021/8/16.
+//
+
+#include <iostream>
+
+using namespace std;
+extern double warming;
+
+void update(double dt);
+
+void local();
+
+int main() {
+    return 0;
+}
+
+void update(double dt) {
+    extern double warming;
+    warming += dt;
+    cout << "Updating global warming to " << warming;
+    cout << "degrees. \n";
+}
+
+void local() {
+    double warming = 0.8;
+    cout << "Local warming = " << warming << " degrees.\n";
+    cout << "But global warming = " << ::warming;
+    cout << " degrees.\n";
+}

base/namespacetest/test10001.cpp

@@ -0,0 +1,17 @@
+//
+// Created by zhuyijun on 2021/8/16.
+//
+
+#include <iostream>
+
+using namespace std;
+
+int main() {
+    int teledeli = 5;
+    {
+        cout << "Hello\n";
+        int websight = -1;
+        cout << websight << ' ';
+    }
+    cout << teledeli << endl;
+}

base/namespacetest/twofile1.cpp

@@ -0,0 +1,26 @@
+//
+// Created by zhuyijun on 2021/8/16.
+//
+
+#include <iostream>
+using namespace std;
+
+int tom = 3;
+int dick = 30;
+static int harry = 300;
+
+void remote_access();
+/**
+ * 编译时请同时编译twofile1.cpp 和twofile2.cpp 命令如下  g++ .\twofile2.cpp .\twofile1.cpp -o test
+ * @return int
+ */
+int main() {
+
+    using namespace std;
+    cout << "main() reports the following address:\n";
+    cout << &tom <<" = &tom, " << &dick <<" = &dick, ";
+    cout << &harry <<" = &harry\n";
+    remote_access();
+    return 0;
+}
+

base/namespacetest/twofile2.cpp

@@ -0,0 +1,18 @@
+//
+// Created by zhuyijun on 2021/8/16.
+//
+
+#include <iostream>
+
+using namespace std;
+
+extern int tom;
+static int dick = 10;
+int harry = 200;
+
+void remote_access() {
+    using std::cout;
+    cout << "remote_access() reports the fllowing addresses:\n";
+    cout << &tom << " = &tom, " << &dick << " = &dick, ";
+    cout << &harry << " = &harry\n";
+}