Add coments in Doxygen style and clearify the code

mygrep/mygrep.c

@@ -15,10 +15,10 @@ int main(int argc, char *argv[]) {
     char *ofile = NULL;
     char *keyword = NULL;
     char *filename = NULL;
-    int c;
+    int c = getopt(argc, argv, "io:h"); ///< Get the options
 
-    // Get the options
+    /// Process the options
-    while((c = getopt(argc, argv, "io:h")) != -1) {
+    while(c != -1) {
         switch(c) {
             case 'i':
                 iflag = 1;
@@ -39,7 +39,7 @@ int main(int argc, char *argv[]) {
         }
     }
 
-     // Check if the required argument is there
+    /// Check if the required argument is there
     if(argv[optind] == NULL) {
         fprintf(stderr, "Mandatory argument 'keyword' missing.\n");
         print_usage();
@@ -49,28 +49,28 @@ int main(int argc, char *argv[]) {
         filename = argv[optind + 1];
     }
 
-    // Get user input if there is no input file defined
+    /// Get user input if there is no input file defined
     while(filename == NULL) {
-        size_t len; // Define an unsigned string length value
+        size_t len; ///< Define an unsigned string length value
 
-        if(getline(&filename, &len, stdin)) {  // Read until new line
+        if(getline(&filename, &len, stdin) != -1) {  ///< Read until new line
             check_for_string(filename, keyword, iflag, ofile);
-            filename = NULL; // Reset the input
+            filename = NULL; ///< Reset the input
         }
     }
 
-    // Get data from input file
+    /// Get data from input file
     if(filename != NULL) {
-        FILE *in;
+        FILE *in = fopen(filename, "r");
-        if((in = fopen(filename, "r")) == NULL) {
+        if(in == NULL) {
             fprintf(stderr, "Error opening the file %s\n", filename);
             exit(EXIT_FAILURE);
         }
 
         size_t len;
-        char *line = NULL; // Define a pointer to hold our value
+        char *line = NULL; ///< Define a pointer to hold our value
 
-        // Read the file line by line and execute check_for_string for each line
+        /// Read the file line by line and execute check_for_string for each line
         while(getline(&line, &len, in) != -1) {
             check_for_string(line, keyword, iflag, ofile);
         }
@@ -132,10 +132,10 @@ static void check_for_string(char *to_check, char *to_find, int iflag, char *ofi
          * If found, append haystack to the end of the file
          * Close the file
          **/
-        FILE *out;
+        FILE *out = fopen(ofile, "a");
 
-        // Check if the file was opened successfully
+        /// Check if the file was opened successfully
-        if((out = fopen(ofile, "a")) == NULL) {
+        if(out == NULL) {
             fprintf(stderr, "Error opening the file %s\n", ofile);
             exit(EXIT_FAILURE);
         }