simplify code and Add emplace_reverse function

Author: fsaadatmand

chapter01/1-19.c

@@ -2,19 +2,18 @@
  * Exercise 1-19. Write a function reverse(s) that reverses the character
  * string s. Use it to write a program that reverses its input a line at a
  * time.
+ *
  * By Faisal Saadatmand
  */
 
 #include <stdio.h>
 
 #define MAXLINE       1000         /* maximum input line length */
-#define YES           1
-#define NO            0
 
 /* functions */
 int  getLine(char [], int);
-int  delTrailingWS(char [], int);
 void reverse(char [], char [], int);
+void emplace_reverse(char [], int);
 
 /* getLine function: read a line into s, return length */
 int getLine(char s[], int lim)
@@ -34,64 +33,39 @@ int getLine(char s[], int lim)
 	return i;
 }
 
-/* delTrailingWS function: deletes trailing whitespaces and blank lines */
-int delTrailingWS(char s[], int len)
+/* reverse function: copy the charaters of  s1 into s2 in reverse order */
+void reverse(char s1[], char s2[], int len)
 {
-	int i, blankLine;
-	int newLength = len;      /* new length of line after whitespaces removal */
-
-	i         = 0;
-	blankLine = NO;
-
-	/* test for blanklines with witespaces */
-	while (s[i] == ' ' || s[i] == '\t' || s[i] == '\n')
-		++i;
-	if (i == len) {          /* remove whitespaces spaces form blank lines */
-		s[0] = '\n';
-		for (i = 1; s[i] != '\0'; ++i)
-			s[i] = '\0';
-		newLength -= i - 1;
-	}
+	int i;
 
-	if (s[0] == '\n') {
-		blankLine = YES;
-	}
+	--len; /* skip the null character '\0' */
+	for (i = 0; s1[i] != '\0'; ++i, --len)
+		s2[len] = s1[i];
 
-	if (!blankLine) {          /* skip entirely blank lines */
-		while (s[len] == '\0' || s[len] == '\n' ||
-				s[len] == ' ' || s[len] == '\t') {
-			s[len] = '\0';
-			--len;
-		}
-		s[len + 1] = '\n';     /* insert newline char before null char */
-		newLength = len + 2;   /* plus 2 for the newline and null characters */
-	}
-	return newLength;
+	s2[i] = '\0';
 }
 
-/* reverse function: reverses char string s1[] and store values into s[2] */
-void reverse(char s1[], char s2[], int len)
+/* emplace_reverse: reverses s's charaters in-place. */
+void emplace_reverse(char s[], int len)
 {
-	int i = 0;
+	int i, j, temp;
 
-	for (--len; s1[i] != '\0'; ++i) {
-		s2[len] = s1[i];
-		--len;
+	for (i = 0, j = len - 1; i < len / 2; ++i, --j) {
+		temp = s[i];
+		s[i] = s[j];
+		s[j] = temp;
 	}
-	s2[i] = '\0';
 }
 
 int main(void)
 {
 	int  len;                   /* current line length */
 	char line[MAXLINE];         /* current input line */
-	char reversedLine[MAXLINE]; 
 
 	while ((len = getLine(line, MAXLINE)) > 0) {
-		len = delTrailingWS(line, len);   /* new length after removing ws */
-		reverse(line, reversedLine, len);
-		printf("%s", reversedLine);
+		line[--len] = '\0';     /* remove newline character at the end */
+		emplace_reverse(line, len);
+		printf("%s\n", line);
 	}
-	printf("\n");
 	return 0;
 }