[ADD CONTENT] C++ Basic Concepts

1_cpp_basics/0_typecasting/explicit_typecasting.cpp

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+// C++ program to demonstrate
+// explicit type casting
+
+#include <iostream>
+using namespace std;
+
+int main()
+{
+	float x = 1.2;
+
+	// Explicit conversion from double to int
+	int sum = (int)x + 1;
+
+	cout << "Sum = " << sum << endl;
+
+	return 0;
+}

1_cpp_basics/0_typecasting/implicit_typecasting.cpp

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+// An example of implicit conversion
+
+#include <iostream>
+using namespace std;
+
+int main()
+{
+	int x = 10;	  // integer x
+	char y = 'a'; // character c
+
+	// y implicitly converted to int. ASCII
+	// value of 'a' is 97
+	x = x + y;
+
+	// x is implicitly converted to float
+	float z = x + 1.0;
+
+	cout << "x = " << x << endl
+		 << "y = " << y << endl
+		 << "z = " << z << endl;
+
+	return 0;
+}

1_cpp_basics/1_namespace/namespace.cpp

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+#include <iostream>
+using namespace std;
+// first name space
+namespace first_space
+{
+	void func()
+	{
+		cout << "Inside first_space" << endl;
+	}
+}
+
+// second name space
+namespace second_space
+{
+	void func()
+	{
+		cout << "Inside second_space" << endl;
+	}
+}
+using namespace first_space;
+int main()
+{
+	// This calls function from first name space.
+	func();
+	return 0;
+}

1_cpp_basics/2_conditional_statements/if.cpp

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+#include <iostream>
+using namespace std;
+int main()
+{
+  int num = 10;
+  if (num > 5) // condition
+  {
+    cout << "Hello From SRA\n";
+    // If condn is fullfilled it will get executed
+  }
+  return 0;
+}

1_cpp_basics/2_conditional_statements/if_else.cpp

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+// Code to find even and odd num using if else statement
+#include <iostream>
+using namespace std;
+int main()
+{
+  int num = 10;
+  if (num % 2 == 0) // if num is divisible by 2 i.e remainder is 0   when divided by 2
+  {
+    cout << "the number is even\n";
+  }
+  else // if If statement is not satisfied the else statement is executed
+  {
+    cout << "The number is odd\n";
+  }
+  return 0;
+}

1_cpp_basics/2_conditional_statements/switch.cpp

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+#include <iostream>
+using namespace std;
+int main()
+{
+  int day = 4;
+  switch (day)
+  {       // Switch statement with day given as condition for cases
+  case 1: // If day=1 then case1 is executed
+    cout << "Monday";
+    break; // if case1 is executed then break is executed and exits switch statement
+  case 2:  // If day=2 then case2 is executed
+    cout << "Tuesday";
+    break; // if case2 is executed then break is executed and exits switch statement
+  case 3:
+    cout << "Wednesday";
+    break;
+  case 4:
+    cout << "Thursday";
+    break;
+  case 5:
+    cout << "Friday";
+    break;
+  case 6:
+    cout << "Saturday";
+    break;
+  case 7:
+    cout << "Sunday";
+    break;
+  default: // If none of the case is satisfied then default statement is executed.
+    cout << "Not a day";
+    break;
+  }
+  return 0;
+}

1_cpp_basics/3_enumeration/enumeration.cpp

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+#include <iostream>
+using namespace std;
+
+enum seasons
+{
+    spring = 34,
+    summer = 4,
+    autumn = 9,
+    winter = 32
+};
+// enum named season is made and spring,summer ,autumn and winter are its member with values 34,5,9,32 respectively
+int main()
+{
+
+    seasons s; // s is a variable of type seasons(enum)
+
+    s = summer; // s is assigned value of summer
+    cout << "Summer = " << s << endl;
+
+    return 0;
+}

1_cpp_basics/4_functions/function.cpp

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+#include <iostream>
+using namespace std;
+
+// Following function that takes two parameters 'x' and 'y'
+// as input and returns max of two input numbers
+int max(int x, int y) // max function made with return type int and parameters int x and int y
+{
+	if (x > y)
+		return x;
+	else
+		return y;
+}
+
+// main function that doesn't receive any parameter and
+// returns integer
+int main()
+{
+	int a = 10, b = 20;
+
+	// Calling above function to find max of 'a' and 'b'
+	int m = max(a, b);
+
+	cout << "m is " << m;
+	return 0;
+}

1_cpp_basics/5_classes_and_objects/classes_and_objects.cpp

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+// C++ program to demonstrate function
+// declaration outside class
+
+#include <iostream>
+using namespace std;
+class Sra
+{
+public:
+	char first_letter;
+	int id;
+
+	// printletter is not defined inside class definition
+	void printletter();
+
+	// printid is defined inside class definition
+	void printid()
+	{
+		cout << "SRA id is: " << id;
+	}
+};
+
+// Definition of printletter using scope resolution operator ::
+void Sra::printletter()
+{
+	cout << "First letter of my name  is: " << first_letter;
+}
+int main()
+{
+
+	Sra obj1;
+	obj1.first_letter = 'v';
+	obj1.id = 24;
+
+	// call printletter()
+	obj1.printletter();
+	cout << endl;
+
+	// call printid()
+	obj1.printid();
+	return 0;
+}

1_cpp_basics/6_templates/class_template.cpp

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+#include <iostream>
+using namespace std;
+template <class T> // Declaring the Class template
+class A
+{
+public:
+    T num1 = 5;
+    T num2 = 6;
+    void add()
+    {
+        std::cout << "Addition of num1 and num2 : " << num1 + num2 << std::endl;
+    }
+};
+
+int main()
+{
+    A<int> d;
+    d.add(); // Calling the class method
+    return 0;
+}

1_cpp_basics/6_templates/functional_template.cpp

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+// Example of Function Template
+
+#include <iostream>
+using namespace std;
+template <class T>
+T add(T &a, T &b) // Declaring a Functional template
+{
+  T result = a + b;
+  return result;
+}
+int main()
+{
+  int i = 2;
+  int j = 3;
+  float m = 2.3;
+  float n = 1.2;
+  cout << "Addition of i and j is :" << add(i, j); // Calling the template for integer data type
+  cout << '\n';
+  cout << "Addition of m and n is :" << add(m, n); // Calling the template for float data type
+  return 0;
+}

1_cpp_basics/7_arrays/arrays2d.cpp

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+#include <iostream>
+using namespace std;
+int main()
+{
+	int arr[4][2] = {// An array with 4 rows and 2 columns is made and initialized
+					 {10, 11},
+					 {20, 21},
+					 {30, 31},
+					 {40, 41}};
+
+	int i, j; // Two variables for looping
+
+	cout << "Printing a 2D Array:\n";
+	for (i = 0; i < 4; i++) // traversing through row
+	{
+		for (j = 0; j < 2; j++) // traversing through column
+		{
+			cout << "\t" << arr[i][j];
+		}
+		cout << endl;
+	}
+	return 0;
+}

1_cpp_basics/7_arrays/passing2darraytofunction.cpp

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+#include <iostream>
+using namespace std;
+
+void display(int (*ptr)[4], int row, int col) // Call by Address
+{
+	int i, j;
+	for (i = 0; i < row; i++)
+	{
+		for (j = 0; j < col; j++)
+			cout << "\t" << *(*(ptr + i) + j); // Array is printed with help of pointer arithmetic
+		cout << "\n";
+	}
+	cout << "\n";
+}
+
+void print(int ptr[][4], int row, int col) // Call by value
+{
+	int i, j;
+	for (i = 0; i < row; i++)
+	{
+		for (j = 0; j < col; j++)
+			cout << "\t" << ptr[i][j];
+		cout << "\n";
+	}
+	cout << "\n";
+}
+
+int main()
+{
+	int a[3][4] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21};
+
+	display(a, 3, 4);
+	print(a, 3, 4);
+	return 0;
+}

1_cpp_basics/8_pointers/pointers.cpp

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+#include <iostream>
+using namespace std;
+int main()
+{
+    int number = 30;
+    int *p;
+    p = &number; // stores the address of number variable
+    cout << "Address of number variable is:" << &number << endl;
+    cout << "Address of p variable is:" << p << endl;
+    cout << "Value of p variable is:" << *p << endl;
+    return 0;
+}

1_cpp_basics/8_pointers/pointers_and_array.cpp

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+#include <iostream>
+using namespace std;
+/* Usage of pointer to an array */
+int main()
+{
+     int a[4][2] = {// Declaring and initialising a 2D array
+                    {1, 2},
+                    {1, 2},
+                    {1, 2},
+                    {1, 2}};
+
+     int(*ptr)[2]; // Declaring a 2D pointer
+     int i, j;
+     for (i = 0; i <= 3; i++)
+     {
+          ptr = &a[i]; // Stores the address of Array a with index i, in ptr
+          cout << "Row" << i << ":";
+          for (j = 0; j <= 1; j++)
+               cout << "\t" << *(*ptr + j); // Prints the data at pointed by address ptr+j
+          cout << endl;
+     }
+     return 0;
+}

1_cpp_basics/9_vectors/access_vector.cpp

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+#include <iostream>
+#include <vector>
+using namespace std;
+
+int main()
+{
+  vector<int> num{1, 2, 3, 4, 5}; // Initialised a vector
+
+  cout << "Element at Index 0: " << num.at(0) << endl; // Printing value at vector index 0
+  cout << "Element at Index 2: " << num.at(2) << endl; // Printing value at vector index 2
+  cout << "Element at Index 4: " << num.at(4);         // Printing value at vector index 4
+
+  return 0;
+}