Table of Contents
- Basic C++ Boilerplate
- Data Types
- Variables
- Operators
- Control Structures
- Conditional Statements
- Loops
- Functions
- Arrays
- Pointers
- Conclusion
1. Basic C++ Boilerplate Code
Boilerplate code is the standard code structure that is required to set up a C++ program. Here is a basic template to start a C++ program:
Basic C++ Program Structure
#include <iostream> // Header file for input and output
using namespace std;
// Main function - execution starts here
int main() {
// Your code goes here
cout << "Hello, World!" << endl; // Output to the console
return 0; // Return 0 to indicate successful execution
}
Explanation of the Boilerplate:
#include <iostream>: This directive includes the input/output stream library, allowing the program to usecoutandcin.using namespace std;: This statement allows the program to use standard library functions without prefixing them withstd::.int main(): This defines the main function, where program execution begins.cout << "Hello, World!" << endl;: This outputs text to the console.return 0;: This signifies that the program ended successfully.
2. Data Types
C++ supports various data types, which can be broadly categorized as follows:
- Fundamental Types:
int,char,float,double,bool - Derived Types:
arrays,functions,pointers - User-defined Types:
struct,class,union,enum
Example:
#include <iostream>
using namespace std;
int main() {
int age = 25; // Integer type
char grade = 'A'; // Character type
float salary = 50000.50; // Floating-point type
bool isEmployed = true; // Boolean type
cout << "Age: " << age << ", Grade: " << grade << ", Salary: " << salary << ", Employed: " << isEmployed << endl;
return 0;
}
3. Variables
Variables are used to store data. They must be declared before use.
Syntax:
// dataType variableName;
int count; // declaration
count = 10; // initialization
Example:
#include <iostream>
using namespace std;
int main() {
int count; // Declaration
count = 10; // Initialization
cout << "Count: " << count << endl;
return 0;
}
4. Operators
C++ provides several types of operators:
- Arithmetic Operators:
+,,,/,% - Relational Operators:
==,!=,<,>,<=,>= - Logical Operators:
&&,||,! - Assignment Operators:
=,+=,=,=,/=,%=
Example:
#include <iostream>
using namespace std;
int main() {
int a = 10, b = 20;
int sum = a + b; // Arithmetic
bool result = (a < b) && (b > 15); // Logical
cout << "Sum: " << sum << ", Result: " << result << endl;
return 0;
}
5. Control Structures
Control structures dictate the flow of control in a program.
Conditional Statements
- If Statement
if (condition) {
// code to execute if condition is true
}
Example:
#include <iostream>
using namespace std;
int main() {
int number = 5;
if (number > 0) {
cout << number << " is positive." << endl;
}
return 0;
}
- Switch Statement
switch (variable) {
case value1:
// code
break;
case value2:
// code
break;
default:
// code
}
Example:
#include <iostream>
using namespace std;
int main() {
int day = 4;
switch (day) {
case 1:
cout << "Monday" << endl;
break;
case 2:
cout << "Tuesday" << endl;
break;
case 3:
cout << "Wednesday" << endl;
break;
case 4:
cout << "Thursday" << endl;
break;
default:
cout << "Invalid day" << endl;
}
return 0;
}
Loops
- For Loop
for (initialization; condition; increment) {
// code to execute
}
Example:
#include <iostream>
using namespace std;
int main() {
for (int i = 0; i < 5; i++) {
cout << "Iteration: " << i << endl;
}
return 0;
}
- While Loop
while (condition) {
// code to execute
}
Example:
#include <iostream>
using namespace std;
int main() {
int count = 0;
while (count < 5) {
cout << "Count: " << count << endl;
count++;
}
return 0;
}
- Do-While Loop
do {
// code to execute
} while (condition);
Example:
#include <iostream>
using namespace std;
int main() {
int count = 0;
do {
cout << "Count: " << count << endl;
count++;
} while (count < 5);
return 0;
}
6. Functions
Functions are reusable blocks of code that perform a specific task.
Syntax:
returnType functionName(parameterList) {
// function body
}
Example:
#include <iostream>
using namespace std;
// Function to add two numbers
int add(int a, int b) {
return a + b;
}
int main() {
int result = add(5, 10); // Function call
cout << "Sum: " << result << endl;
return 0;
}
7. Arrays
Arrays are used to store multiple values of the same data type in a single variable.
Declaration:
dataType arrayName[arraySize];
Example:
#include <iostream>
using namespace std;
int main() {
int numbers[5] = {1, 2, 3, 4, 5}; // Declaration and initialization
for (int i = 0; i < 5; i++) {
cout << "Number at index " << i << ": " << numbers[i] << endl;
}
return 0;
}
8. Pointers
Pointers are variables that store the memory address of another variable.
Declaration:
dataType* pointerName;
Example:
#include <iostream>
using namespace std;
int main() {
int num = 10;
int* ptr = # // Pointer to num
cout << "Value of num: " << num << endl;
cout << "Address of num: " << &num << endl;
cout << "Value of ptr: " << ptr << endl; // Address of num
cout << "Value pointed to by ptr: " << *ptr << endl; // Dereferencing ptr
return 0;
}