Moving on to Chapter 2

ch_01/exercise_01-23/main.c

@@ -0,0 +1,173 @@
+/*
+ *
+ * Exercise 1-23. Write a program to remove all comments from a c program. Don't forget to
+ * handle quoted strings and character constants properly. C comments don't nest.
+ *
+ * This program assumes that the user will enter a syntactically correct c program.
+ *
+ * Author: Kun Deng
+ */
+
+#include <stdio.h>
+
+#define LINE_MAX_COUNT 1000 // The max amount of characters accepted for a line
+#define PROGRAM_MAX_CHARACTER_COUNT 10000 // The max amount of characters allowed for the c program
+
+// The two symbolic constants server to check if currently in a quote. Comments will not
+// be removed if within quotes
+#define IN_QUOTES 1
+#define OUT_QUOTES 0
+
+#define NO_COMMENT_STATE 0
+#define SINGLE_COMMENT_STATE  1
+#define MULTI_LINE_COMMENT_START_STATE 2
+#define MULTI_LINE_COMMENT_END_STATE 3
+
+char line[LINE_MAX_COUNT];
+char c_program[PROGRAM_MAX_CHARACTER_COUNT];
+
+int c_program_length = 0;
+
+int get_line(void);
+// Returns 1 if line contains comments, 2 if the line begins with a multi-line comment specifier,
+// 3 if the trailing multi-line comment specifier is found
+// and 0 if no comments found
+int line_contains_comments(int line_length);
+
+void copy_line(int line_length);
+
+
+int main()
+{
+    printf("Enter a simple C program that contains comments.\n");
+    printf("Comments will be removed and the end result will be the c program ");
+    printf("without comments.\n");
+    
+    extern char line[];
+    extern char c_program[];
+
+    extern int c_program_length;
+
+    int length = 0;
+    int comment_state = NO_COMMENT_STATE;
+
+    while (length = get_line())
+    {
+        int current_state = line_contains_comments(length);
+
+        // printf("current state %d\n", current_state);
+        // printf("line %s\n", line);
+        
+        if (current_state == SINGLE_COMMENT_STATE)
+        {
+            comment_state = current_state;
+        }
+        else if (current_state == MULTI_LINE_COMMENT_START_STATE)
+        {
+            comment_state = current_state;
+        }
+        else if (current_state == NO_COMMENT_STATE && 
+                comment_state != MULTI_LINE_COMMENT_START_STATE)
+        {
+            comment_state = current_state;
+        }
+
+        if (comment_state == MULTI_LINE_COMMENT_START_STATE && 
+                current_state == MULTI_LINE_COMMENT_END_STATE)
+        {
+            comment_state = current_state;
+        }
+
+        if (comment_state == NO_COMMENT_STATE)
+        {
+            copy_line(length);
+        }
+    }
+
+    c_program[c_program_length] = '\0';
+
+    printf("\n\nC program without comments\n\n%s\n", c_program);
+
+    return 0;
+}
+
+int get_line(void)
+{
+    extern char line[];
+    int c;
+    int length = 0;
+
+    for (; (c = getchar()) != EOF && c != '\n'; ++length)
+    {
+        line[length] = c;
+    }
+
+    line[length] = '\0';
+
+    return length;
+}
+
+int line_contains_comments(int line_length)
+{
+    extern char line[];
+
+    int result = NO_COMMENT_STATE; // Defaulting to no comments found
+    int state = OUT_QUOTES;
+    int quote_count = 0; // Resets the state if quote count is 2
+
+    for (int i = 0; i != line_length; ++i)
+    {
+        int c = line[i];
+
+        if (c == '"')
+        {
+            ++quote_count;
+
+            if (quote_count == 2)
+            {
+                quote_count = 0;
+                state = OUT_QUOTES;
+            }
+            else
+            {
+                state = IN_QUOTES;
+            }
+        }
+
+        if (state == OUT_QUOTES && c == '/' && i > 0 && (line[i - 1] == '/'))
+        {
+            result = SINGLE_COMMENT_STATE; // Found comment
+            // printf("found single-line comment\n");
+        }
+        else if (state == OUT_QUOTES && c == '*' && i > 0 && (line[i - 1] == '/'))
+        {
+            result = MULTI_LINE_COMMENT_START_STATE; // Found multi-line comment start
+            // printf("found start of multi-line comment\n");
+        }
+        else if (state == OUT_QUOTES && c == '/' && i > 0 && (line[i - 1] == '*'))
+        {
+            result = MULTI_LINE_COMMENT_END_STATE; // Found multi-line comment end
+            // printf("found end of multi-line comment\n");
+        }
+    }
+
+    return result;
+}
+
+
+void copy_line(int line_length)
+{
+    extern char line[];
+    extern char c_program[];
+
+    extern int c_program_length;
+
+    // printf("copying line\n");
+
+    for (int i = 0; i != line_length; ++i)
+    {
+        c_program[c_program_length++] = line[i];
+    }
+
+    c_program[c_program_length++] = '\n';
+}

ch_01/exercise_01-23/main_template.c

@@ -1,6 +0,0 @@
-/*
- *
- * Exercise 
- *
- * Author: Kun Deng
- */