#include<stdio.h>
#include<string.h>
#include<ctype.h>

void cap_all(char* text){
	for(char *i = text; *i; i++)
		*i = toupper(*i);
}

void lower_all(char* text){
	for(char *i = text; *i; i++)
		*i = tolower(*i);
}

void remove_space(char* text){
	for(char *i = text; *i; i++)
		if(*i == ' ')
			*i = '_';
}

void apply_and_print(char* text, void (*to_apply)(char*)){
	to_apply(text);
	puts(text);
}

void (*return_cycle())(char*){
	void (*functions[])(char*) = {cap_all, lower_all, remove_space};
	size_t nfun = sizeof(functions) / sizeof(functions[0]);
	static int current = 0;
	current++;
	if(current >= nfun)
		current = 0;
	return functions[current];
}

int main(){
	char story[] = "There was a moose in the living room.  It went ...";

	void (*my_name_that_I_like_better)(char*);
//	Maybe we would have expected this instead:
//	void (*)(char*) my_name_that_I_like_better;
	my_name_that_I_like_better = lower_all;

	my_name_that_I_like_better(story);
	puts(story);
	my_name_that_I_like_better = cap_all;
	my_name_that_I_like_better(story);
	puts(story);

	apply_and_print(story, cap_all);
	apply_and_print(story, lower_all);
	apply_and_print(story, remove_space); 
	char another_story[] = "The mouse had spectacles that were cracked.  It ...";
	return_cycle()(another_story);
	puts(another_story);
	return_cycle()(another_story);
	puts(another_story);
	return_cycle()(another_story);
	puts(another_story);
	return_cycle()(another_story);
	puts(another_story);
	return_cycle()(another_story);
	puts(another_story);

	return 0;
}