Digitsum (n) enters a nonnegative integer that returns the sum of the numbers that comprise it, calls Digitsum (1729), returns 1+7+2+9, and 19

/* Write a recursive function digitsum (n), enter a nonnegative integer, return the sum of the numbers that make up it, for example, call Digitsum (1729), then return to 1+7+2+9, which is 19*/#include <stdio.h># Include<math.h>int digitsum (int n) {int static sum = 0;IF (n! = 0) {sum + = n% 10;digitsum (N/10);} return sum;} int main (void) {//printf ("%d\n", Digitsum (1728));p rintf ("%d\n", Digitsum (1729)); return 0;}

It is worth noting that here I used the static variable sum, One of the functions of static is to keep the contents of the variable persistent. Variables stored in the static data area are initialized at the start of the program and are the only one initialized. Otherwise, the sum of sums is executed only once.

Digitsum (n) enters a nonnegative integer, returns the sum of the numbers that comprise it, calls Digitsum (1729), returns 1+7+2+9, and