init commit

3sem/cnts/contest11/05.c

@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <wait.h>
+#include <sys/types.h>
+
+int
+main()
+{
+
+    pid_t pid;
+    int n;
+
+    pid = fork();
+    if (!pid) {
+        for (;;) {
+            if (scanf("%d", &n) != 1) {
+                return 0;
+            }
+
+            pid = fork();
+            if (!pid) {
+                continue;
+            }
+            int status;
+            wait(&status);
+            if (pid == -1 || !WIFEXITED(status) || WEXITSTATUS(status)) {
+                return -1;
+            }
+
+            printf("%d\n", n);
+            return 0;
+        }
+    } else {
+        int status;
+        wait(&status);
+        if (pid == -1 || !WIFEXITED(status) || WEXITSTATUS(status)) {
+            printf("-1\n");
+        }
+    }
+
+    return 0;
+}