Main.cpp

Memory Helper Functions

Main.cpp

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#include <iostream>
#include <cstdlib>
#include <memory>
#include <vector>
#include <cstring>
class MyClass {
public:
    MyClass() { std::cout << "MyClass constructed\n"; }
    ~MyClass() { std::cout << "MyClass destructed\n"; }
};
int main() {
    // 1. new and delete operators
    std::cout << "1. new and delete operators:\n";
    MyClass* ptr = new MyClass();
    delete ptr;
    int* arr = new int[5];
    delete[] arr;
    // 2. C-style memory management
    std::cout << "\n2. C-style memory management:\n";
    int* c_ptr = (int*)malloc(sizeof(int));
    *c_ptr = 10;
    std::cout << "malloc: " << *c_ptr << std::endl;
    free(c_ptr);
    int* c_arr = (int*)calloc(5, sizeof(int));
    std::cout << "calloc: " << c_arr[0] << std::endl;  // Will be 0
    c_arr = (int*)realloc(c_arr, 10 * sizeof(int));
    free(c_arr);
    
    // memset with integers (be cautious!)
    int numbers[5] = {1, 2, 3, 4, 5};
    std::cout << "\nBefore memset: ";
    for (int i = 0; i < 5; ++i) std::cout << numbers[i] << " ";
    std::cout << std::endl;
    
    memset(numbers, 0, sizeof(numbers));
 
 
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STDIN

Output:

1. new and delete operators:
MyClass constructed
MyClass destructed

2. C-style memory management:
malloc: 10
calloc: 0

Before memset: 1 2 3 4 5 
After memset:  0 0 0 0 0 

memcpy example:
Source: Hello, memcpy!
Destination: Hello, memcpy!

3. Smart Pointers:
MyClass constructed
MyClass constructed

4. Allocator:
Allocator: 42

5. Other memory-related functions:
addressof: 0x7fff2558b774
uninitialized_copy: 3

8. Placement new:
MyClass constructed
MyClass destructed
MyClass destructed
MyClass destructed

created 1 year ago by Tej Pratap Singh

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About C++

C++ is a widely used middle-level programming language.

Supports different platforms like Windows, various Linux flavours, MacOS etc
C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
Case-sensitive
C++ is a compiler based language
C++ supports structured programming language
C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}