Reverse words in a string

Signed-off-by: begeekmyfriend <[email protected]>

Author: begeekmyfriend

151_reverse_words_in_a_string/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test reverse.c

151_reverse_words_in_a_string/reverse.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static reverse(char *s, int lo, int hi)
+{
+    while (lo < hi) {
+        char c = s[lo];
+        s[lo] = s[hi];
+        s[hi] = c;
+        lo++;
+        hi--;
+    }
+}
+
+static void reverseWords(char *s)
+{
+    int i = 0, j = 0;
+    while (s[i] != '\0') {
+        while (s[i] == ' ') {
+            i++;
+        }
+        if (s[i] == '\0') break;
+        while (s[i] != '\0' && s[i] != ' ') {
+            s[j++] = s[i++];
+        }
+        s[j++] = s[i];
+    }
+    s[j] = '\0';
+    s[--j] = '\0';
+    reverse(s, 0, j - 1);
+
+    for (i = 0, j = 0; s[i] != '\0';) {
+        for (j = i; s[j] != '\0' && s[j] != ' '; j++) {}
+        reverse(s, i, j - 1);
+        for (i = j; s[i] != '\0' && s[i] == ' '; i++) {}
+    }
+}
+
+int main(int argc, char **argv)
+{
+    if (argc != 2) {
+        fprintf(stderr, "Usage: ./test string\n");
+        exit(-1);
+    }
+    reverseWords(argv[1]);
+    printf("%s\n", argv[1]);
+    return 0;
+}