Is there any hard-wired limit on recursion depth in C

Question

The program under discussion attempts to compute sum-of-first-n-natural-numbers using recursion. I know this can be done using a simple formula n

Answer 1

1)Consumption of the stack is expected to be reduced and written as tail recursion optimization.

gcc -O3 prog.c

#include 

unsigned long long int add(unsigned long int n, unsigned long long int sum){
    return (n == 0) ? sum : add(n-1, n+sum); //tail recursion form
}

int main(){
    printf("result : %llu \n", add(1000000, 0));//OK
    return 0;
}