Dynamic get string

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

char* gets_dynamic()
{
    char* s = NULL, c = NULL;
    int len = 1;
    while((c = getchar()) != '\n')
    {
        s = (char*)realloc(s, ++len);
        s[len-2] = c;
    }
    s[len-1] = NULL;
    return s;
}

int main()
{
    char* s = gets_dynamic();
    puts(s);
    free(s);
    return 0;
}