finished cls11

src/cls11/main.c

@@ -3,8 +3,10 @@
 
 #define BUFF_SZ 128
 
-// Lenght of string including null terminator
+// Obtain the lenght of string
 int my_strlen(char *str, int max_len) {
+    if (str == NULL) return -1;
+
     int i = 0;
     while (*(str + i) != '\0' && i < max_len)
         i++;
@@ -14,6 +16,8 @@ int my_strlen(char *str, int max_len) {
 
 // convert ASCII CAPITAL CASE ALPHABETS into lower case alphabets
 void to_lower(char *str, int sz) {
+    if (str == NULL) return;
+
     for (int i = 0; i < sz; i++) {
         if (*(str + i) >= 'A' && *(str + i) <= 'Z') {
             *(str + i) = *(str + i) + 0x20;
@@ -23,12 +27,12 @@ void to_lower(char *str, int sz) {
 
 // remove every non-alphabet letters from string
 int strip(char *str, char *dest, int sz) {
-    int ret_sz = 0;
-
     if (str == NULL || dest == NULL) {
         return -1;
     }
 
+    int ret_sz = 0;
+
     for (int i = 0; i < sz; i++) {
         if (*(str + i) >= 'a' && *(str + i) <= 'z') {
             *(dest + ret_sz) = *(str + i);
@@ -43,6 +47,8 @@ int strip(char *str, char *dest, int sz) {
 
 // check if string is a palindrome
 bool kaibun(char *str, int sz) {
+    if (str == NULL) return false;
+
     for (int i = 0; i < (sz - 1)/2; i++) {
         if (*(str + i) != *(str + sz - i - 2)) {
             return false;
@@ -53,28 +59,28 @@ bool kaibun(char *str, int sz) {
 }
 
 int main(void) {
-    char *b = (char*)malloc(sizeof(char) * (BUFF_SZ + 1)); // BUFF_SZ letters + null terminator
-    char *t = (char*)malloc(sizeof(char) * (BUFF_SZ + 1));
+    // BUFF_SZ letters + null terminator
+    char *buff = (char*)malloc(sizeof(char) * (BUFF_SZ + 1)); 
+    char *processed_str = (char*)malloc(sizeof(char) * (BUFF_SZ + 1));
     
     printf("Input string: ");
-    char* res = fgets(b, BUFF_SZ, stdin);
+    char* res = fgets(buff, BUFF_SZ, stdin);
     if (res == NULL) {
         printf("Error while reading from stdin\n");
-        return 0;
+        return 1;
     }
 
-    int len = my_strlen(b, BUFF_SZ);
+    int len = my_strlen(buff, BUFF_SZ);
+    if (len == -1) {
+        printf("Error on retrival of string length.");
+        return 1;
+    }
+    to_lower(buff, len);
+    len = strip(buff, processed_str, len);
 
-    printf("len: %d\n", len);
-    
-    to_lower(b, len);
-    len = strip(b, t, len);
+    bool isPalindrome = kaibun(processed_str, len + 1);
 
-    printf("len: %d\n", len);
-
-    bool isPalindrome = kaibun(t, len + 1);
-
-    printf("isPalindrome: %d\n", isPalindrome);
+    printf("isPalindrome: %s\n", isPalindrome ? "true" : "false");
 
     return 0;
 }