55 lines
989 B
C
55 lines
989 B
C
#include <stdio.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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int collatz(int, int[], int);
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void print_buffer(int buff[]);
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int main(int argc, char *argv[]) {
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if (argc < 2) {
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perror("Usage: collatz NUMBER\n");
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return EXIT_FAILURE;
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}
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int n = atoi(argv[1]);
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if (n <= 1) {
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perror("The number MUST be greater than 1\n");
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return EXIT_FAILURE;
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}
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printf("Collatz of %d\n", n);
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pid_t pid = fork();
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if (pid == 0) {
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int buff[1024] = {0};
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collatz(n, buff, 0);
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print_buffer(buff);
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} else if (pid > 0) {
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wait(NULL);
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}
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return EXIT_SUCCESS;
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}
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int collatz(int n, int buff[], int steps) {
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buff[steps] = n;
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if (n == 1) {
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return n;
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} else if (n % 2 == 0) {
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return collatz(n / 2, buff, steps + 1);
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} else {
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return collatz(3 * n + 1, buff, steps + 1);
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}
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}
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void print_buffer(int buff[]) {
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int i = 0;
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while (buff[i] != 0) {
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printf("%d ", buff[i]);
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i++;
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}
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printf("\n");
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}
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