3.2

1 files changed, 91 insertions, 0 deletions

diff --git a/3/2.c b/3/2.c
new file mode 100644
index 0000000..f6f6987
--- /dev/null
+++ b/3/2.c
@@ -0,0 +1,91 @@
+#include <stdio.h>
+#include <string.h>
+
+#define ESCAPE 0
+#define UNESCAPE 1
+#define MAXLEN 1000
+
+/* convert new line and tab chars to visible chars */
+void escape(char s[], char t[]);
+
+/* converts escapes sequences to chars */
+void unescape(char s[], char t[]);
+
+int main(int argc, char *argv[]) {
+  int c, i, cmd;
+  char s[MAXLEN], t[MAXLEN];
+
+  if (!strcmp(argv[1], "e"))
+    cmd = ESCAPE;
+  else if (!strcmp(argv[1], "u"))
+    cmd = UNESCAPE;
+  else
+    return 1;
+
+  printf("Enter string to %s and press Ctrl+D\n",
+         cmd == ESCAPE ? "escape" : "unescape");
+
+  for (i = 0; i < MAXLEN - 1 && (c = getchar()) != EOF; i++)
+    t[i] = c;
+  t[i] = 0;
+
+  if (cmd == ESCAPE) {
+    escape(s, t);
+    printf("Escaped output:\n");
+    printf("%s\n", s);
+  } else if (cmd == UNESCAPE) {
+    unescape(s, t);
+    printf("Unescaped output:\n");
+    printf("%s\n", s);
+  } else {
+    return 1;
+  }
+
+  return 0;
+}
+
+void escape(char s[], char t[]) {
+  int c, i, j;
+
+  for (i = 0, j = 0; (c = t[i]) != 0; i++) {
+    switch (c) {
+    case '\n': {
+      s[j++] = '\\';
+      s[j++] = 'n';
+      break;
+    }
+    case '\t': {
+      s[j++] = '\\';
+      s[j++] = 't';
+      break;
+    }
+    default:
+      s[j++] = c;
+    }
+
+    s[j] = 0;
+  }
+}
+
+void unescape(char s[], char t[]) {
+  int c, i, j;
+
+  for (i = 0, j = 0; (c = t[i]) != 0; i++) {
+    if (j > 0 && s[j - 1] == '\\') {
+      switch (c) {
+      case 'n':
+        s[j - 1] = '\n';
+        break;
+      case 't':
+        s[j - 1] = '\t';
+        break;
+      default:
+        s[j++] = c;
+      }
+    } else {
+      s[j++] = c;
+    }
+  }
+
+  s[j] = 0;
+}
\ No newline at end of file