1 files changed, 47 insertions, 0 deletions

diff --git a/1/20.c b/1/20.c
new file mode 100644
index 0000000..a4f38cb
--- /dev/null
+++ b/1/20.c
@@ -0,0 +1,47 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAXLEN 1000
+
+void getstr(char s[]);
+void detab(char to[], char from[], int n);
+
+/* detabs input by replacing tabs with specified number of blanks */
+int main(int argc, char *argv[]) {
+  char s[MAXLEN], dtab[MAXLEN];
+  int tabw = atoi(argv[1]);
+
+  printf("Enter text to detab and press ctrl+d\n");
+
+  getstr(s);
+  detab(dtab, s, tabw);
+
+  printf("\nTab width: %d\n", tabw);
+  printf("%s\n", dtab);
+
+  return 0;
+}
+
+void getstr(char s[]) {
+  int i, c;
+
+  for (i = 0; i < MAXLEN - 1 && (c = getchar()) != EOF; i++)
+    s[i] = c;
+  s[i] = '\0';
+}
+
+void detab(char to[], char from[], int n) {
+  int i, j, k;
+  char c;
+
+  for (i = 0, j = 0; j < MAXLEN - 1 && (c = from[i]) != '\0'; i++) {
+    if (c == '\t') {
+      for (k = 0; k < n; k++)
+        to[j++] = ' ';
+    } else {
+      to[j++] = from[i];
+    }
+  }
+
+  to[j] = '\0';
+}
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