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99-bottles.c
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99-bottles.c
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/**
* Hayden Walker
* 2023-10-05
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
void print_beers(int beers);
/**
* Display the lyrics to '99 bottles of beer' by creating
* a child process to display each verse.
*
* Inspired by: http://www.99-bottles-of-beer.net/
*/
int main()
{
int beers = 99, status;
pid_t pid;
while(beers >= 0) {
pid = fork();
switch(pid) {
case -1:
// failed to create a child process
exit(EXIT_FAILURE);
case 0:
// this process is a child process
print_beers(beers);
exit(EXIT_SUCCESS);
default:
// this process is the parent process
printf("This beer's PID: %d\n", pid);
waitpid(pid, &status, 0);
beers--;
}
}
exit(EXIT_SUCCESS);
}
/**
* Print the verse for `beers` number of beers.
*/
void print_beers(int beers)
{
switch(beers) {
case 0:
printf("No more bottles of beer on the wall, ");
printf("no more bottles of beer.\n");
printf("Go to the store and buy some more, ");
printf("99 bottles of beer on the wall.\n");
break;
case 1:
printf("1 bottle of beer on the wall, ");
printf("1 bottle of beer.\n");
printf("Take one down and pass it around, ");
printf("no more bottles of beer on the wall.\n\n");
break;
default:
printf("%d bottles of beer on the wall, ", beers);
printf("%d bottles of beer.\n", beers);
printf("Take one down and pass it around, ");
printf("%d %s of beer on the wall.\n\n",
beers - 1, beers - 1 > 1 ? "bottles" : "bottle");
break;
}
}