Finish Ch. 1

ch_1/initialization/main.cpp

@@ -5,7 +5,11 @@ int main() {
     double pi { 3.1415 };
     [[maybe_unused]] double tau { 6.2830 };
 
-    std::cout << pi;
+    std::cout << pi << std::endl;
+
+    int y;
+
+    std::cout << "y is uninitialized. it's value is " << y << "\n";
 
     return 0;
 }

ch_1/your_first_program/Makefile

@@ -0,0 +1,8 @@
+all:
+	g++ main.cpp -o main -O2 -DNDEBUG -pedantic-errors -Wall -Weffc++ -Wextra -Wconversion -Wsign-conversion -std=c++23
+
+debug:
+	g++ main.cpp -o main -ggdb -pedantic-errors -Wall -Weffc++ -Wextra -Wconversion -Wsign-conversion -std=c++23
+
+clean:
+	rm -r main

ch_1/your_first_program/main.cpp

@@ -0,0 +1,12 @@
+#include <iostream>
+
+int main() {
+    std::cout << "Enter an integer: ";
+
+    int num{ };
+    std::cin >> num;
+
+    std::cout << "Double your number is " << num * 2 << "\n";
+
+    return 0;
+}