Lambda and Closures

C does not directly support higher-order functions. However, function pointers in C can be used to achieve similar behavior.

#include <stdio.h>

typedef int (*func_ptr)(int);

int do_twice(func_ptr f, int arg) {
    return f(arg) + f(arg);
}

int add_one(int x) {
    return x + 1;
}

int main() {
    int answer = do_twice(add_one, 5);
    printf("The answer is: %d\n", answer); // Prints: The answer is: 12
    return 0;
}

In JavaScript:

function doTwice(f, arg) {
    return f(arg) + f(arg);
}

function main() {
    const answer = doTwice(x => x + 1, 5);
    console.log(`The answer is: ${answer}`); // Prints: The answer is: 12
}

main();

In C programming, closures can be simulated using function pointers and structures. By encapsulating data and functions within a structure, C can achieve a form of closures. This approach allows functions to access variables from their enclosing scope even after the scope has exited. The structure holds the data and function pointers, enabling the functions to operate on the enclosed data. While C does not have native closure support like some other languages, this workaround provides a mechanism for achieving similar functionality. By leveraging function pointers and structures, C programmers can implement closures effectively within their code.