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

struct c_list{
	char c; // The character
	int  n; // how many times it's been seen before.
	struct c_list* next; // pointer to the next node
};

void add(struct c_list* node, char c){
	if (node->c == c){
		// Case one: we find our node
		node->n++; // increase its count
	} else if (node->next){
		// Case two: we didn't find our node, but there are more
		add(node->next, c); // add c to the next node
	} else {
		// Case three: we've reached the end
		node->next = (struct c_list*)malloc(sizeof(struct c_list));
		node->next->c = c;
		node->next->n = 1;
		node->next->next = 0;
	}
}

void traverse_and_print(struct c_list* node){
	if (!node) return; // termination condition
	printf("%c-%d\n", node->c, node->n);
	traverse_and_print(node->next);
	// After recursion, we free the memory from right to left
	// we can implement a simple stack check here to
	// make sure that we're not freeing from the stack,
	// but that seems unnecessary.
	/*
		void* stackptr = &node;
		if (node < stackptr-0x1000)
	*/
	free(node);
}

int main(int argc, char** argv){
	struct c_list parent = {(char)EOF, 0, 0}; // sentinel header
	for(;argc>1;argc--){
		char *arg = *++argv; // argv[0] is filename
		while (*arg){ // C strings are null terminated
			char c = *arg++;
			add(&parent, c); // add the char into the LL
		}
	}
	traverse_and_print(parent.next); // Print the contents of the LL
	return 0;
}