Convert long type to string type in C language

long to string in c example:

/*
convert long to string in C language
*/

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <assert.h>

int main()
{
    long unsigned int ulong_value = 123456;
    const int n = snprintf(NULL, 0, "%lu", ulong_value);
    assert(n > 0);
    char buf[n+1];
    int c = snprintf(buf, n+1, "%lu", ulong_value);
    assert(buf[n] == '\0');
    assert(c == n);
    printf("string: %s",buf);

    return 0;
}