Generated on 2021-02-25

Author: cpp-tutor

headers/01-hellow.cpp

@@ -0,0 +1,8 @@
+// 01-hellow.cpp : prints a line of text to the console
+
+#include <iostream>
+using namespace std;
+
+int main() {
+    cout << "Hello, World!" << '\n';
+}

headers/01-title.cpp

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+// 01-title.cpp : output the title page of a well-known book
+
+#include <iostream>
+using namespace std;
+
+int main() {
+    cout << 1+R"(
+                   Alice's
+                Adventures In
+                 Wonderland
+
+                     by
+                LEWIS CARROLL
+)";
+}

headers/02-assign.cpp

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+// 02-assign.cpp : assign to local variables
+
+#include <iostream>
+using namespace std;
+
+int main() {
+    int i = 1, j = 2;
+    unsigned k;
+    cout << "(1) i = " << i << ", j = " << j << ", k = " << k << '\n';
+    i = j;
+    j = 3;
+    k = -1;
+    cout << "(2) i = " << i << ", j = " << j << ", k = " << k << '\n';
+}

headers/02-constants.cpp

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+// 02-constants.cpp : introducing the const keyword
+
+#include <iostream>
+using namespace std;
+
+const double PI = 3.14159265358979;
+
+int main() {
+    auto const APPROX_E = 3;
+    cout << "pi is almost exactly " << PI
+    << "e is approximately " << APPROX_E
+    << '\n';
+}

headers/02-constexpr.cpp

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+// 02-constexpr.cpp : introducing the constexpr keyword
+
+#include <iostream>
+#include <cmath>
+using namespace std;
+
+const double PI1 = acos(-1.0);     // acos is not (yet) constexpr
+constexpr double PI2 = 22.0 / 7.0;
+
+// the following line does not compile and has been commented out
+//static_assert(PI1 > 3.141 && PI1 < 3.143);
+static_assert(PI2 > 3.141 && PI2 < 3.143);
+
+int main() {
+    cout << "PI1 = " << PI1 << '\n';
+    cout << "PI2 = " << PI2 << '\n';
+}

headers/02-height.cpp

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+// 02-height.cpp : define the same variable name in two different namespaces
+
+#include <iostream>
+using namespace std;
+
+namespace Wonderland {
+    auto alice_height_m{ 0.15 };
+}
+
+namespace VictorianEngland {
+    auto alice_height_m{ 0.9 };
+}
+
+int main() {
+    cout << "Alice\'s height varies between "
+    << Wonderland::alice_height_m
+    << "m and "
+    << VictorianEngland::alice_height_m
+    << "m.\n";
+}

headers/02-references.cpp

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+// 02-references.cpp : introducing l-value references
+
+#include <iostream>
+using namespace std;
+
+int alice_age{ 9 };
+
+int main() {
+    cout << "Alice\'s age is " << alice_age << '\n';
+    int& alice_age_ref = alice_age;
+    alice_age_ref = 10;
+    cout << "Alice\'s age is now " << alice_age << '\n';
+}

headers/02-scopes.cpp

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+// 02-scopes.cpp : define three variables with the same name in one program
+
+#include <iostream>
+using namespace std;
+
+auto a{ 1.5f };
+
+int main() {
+    cout << "(1) " << a << '\n';
+    auto a{ 2u };
+    cout << "(2) " << a << '\n';
+    {
+        auto a{ 2.5 };
+        cout << "(3) " << a << '\n';
+    }
+}

headers/02-swap.cpp

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+// 02-swap.cpp : attempt to swap the values of an int and a double
+
+#include <iostream>
+using namespace std;
+
+int main() {
+    int a = 1;
+    double b = 2.5;
+    cout << "(1) a = " << a << ", b = " << b << '\n';
+    a = 2.5;
+    b = 1;
+    cout << "(2) a = " << a << ", b = " << b << '\n';
+}

headers/02-uniform.cpp

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+// 02-uniform.cpp : avoid compiler error with uniform initialization and explicit narrowing cast
+
+#include <iostream>
+using namespace std;
+
+int main() {
+    // int c = { 2.5 };                 // Error: this does NOT compile
+    int c = { static_cast<int>(2.5) };  // while this does
+    double d = { 1 };                   // and so does this
+    cout << "c = " << c << ", d = " << d << '\n';
+}