new

Allocates memory from the free store (heap) and constructs an object in that memory. Returns a pointer to the constructed object.

Syntax

Type* ptr = new Type;                    // default-initialize
Type* ptr = new Type(args);              // direct-initialize
Type* ptr = new Type{args};              // list-initialize
Type* arr = new Type[n];                 // array allocation
Type* ptr = new (placement) Type(args);  // placement new

Example

#include <print>
#include <memory>

struct Node {
    int val;
    Node* next;
    Node(int v) : val(v), next(nullptr) {}
};

int main() {
    // Direct allocation and deletion
    Node* n = new Node(42);
    std::println("{}", n->val);
    delete n;

    // Array allocation
    int* arr = new int[5]{1, 2, 3, 4, 5};
    std::println("{}", arr[2]);
    delete[] arr;

    // Prefer smart pointers in production code
    auto p = std::make_unique<Node>(99);
    std::println("{}", p->val);   // auto-deleted when p goes out of scope
}

Notes

• Raw new/delete should be avoided in application code; use std::make_unique / std::make_shared instead.
• On allocation failure, new throws std::bad_alloc; use new (std::nothrow) for a non-throwing version.
• Always pair array new[] with array delete[].
• cppreference: new