add : string with functios 10

Author: webwithaman

14_string_with_functions/10_is_palindrome.c

@@ -1,4 +1,4 @@
-// Write a c program to reverse a string using user-defined function.
+// Write a function to check whether a given string is palindrome or not
 
 // Header Files
 #include <stdio.h>
@@ -10,20 +10,23 @@
 // Function Declarations
 int strLength(char[]);
 char *strReverse(char[]);
+char *copyString(char[], char[]);
+int compareStrings(char[], char[]);
 int isStrPalindrome(char[]);
 
 // Main Function Start
 int main()
 {
     char str[ARRAY_SIZE];
 
-    printf("\nEnter Any String (MAX CHARACTERS %d) => ", ARRAY_SIZE - 1);
+    printf("\nEnter Any String to Check Whether It is Palindrome or Not (MAX CHARACTERS %d) => ", ARRAY_SIZE - 1);
     fgets(str, ARRAY_SIZE, stdin);  // Input String
     str[strcspn(str, "\n")] = '\0'; // Replace '\n' character with '\0' in str
 
-    printf("\nString Before Reversing => %s", str);
-
-    printf("\nString After Reversing => %s", strReverse(str));
+    if (isStrPalindrome(str))
+        printf("\nYes, \"%s\" is Palindrome...", str);
+    else
+        printf("\nNo, \"%s\" is not Palindrome...", str);
 
     putch('\n');
     getch();
@@ -47,14 +50,10 @@ int strLength(char str[])
 // Function to Reverse a String
 char *strReverse(char str[])
 {
-    int length = 0;
+    int length = strLength(str);
     char temp;
 
-    // Find Length of str
-    while (str[length])
-        length++;
-
-    // // Reverse copyStr
+    // Reverse str
     int beg = 0, end = length - 1;
     while (beg < end)
     {
@@ -69,11 +68,42 @@ char *strReverse(char str[])
     return str;
 }
 
+// Function to Copy One String into Another
+char *copyString(char des[], char src[])
+{
+    // Copy str into copy
+    int i = 0;
+    for (i = 0; src[i]; i++)
+        des[i] = src[i];
+
+    des[i] = '\0';
+
+    return des;
+}
+
+// Function to Check Whether a Given String an Alphanumeric String or Not
+int compareStrings(char str1[], char str2[])
+{
+    for (int i = 0; str1[i] || str2[i]; i++)
+    {
+        if (str1[i] > str2[i])
+            return str1[i] - str2[i];
+        else if (str1[i] < str2[i])
+            return str1[i] - str2[i];
+    }
+
+    return 0;
+}
+
 // Function to Check Whether a Given String is Palindrome or Not
 int isStrPalindrome(char str[])
 {
+    char copyStr[strLength(str) + 1]; // create a string to copy str
+    copyString(copyStr, str);         // copy str into copyStr
+    strReverse(copyStr);              // reverse copyStr
 
-    if (copyStr)
+    if (compareStrings(copyStr, str))
+        return 0; // String is not Palindrome
 
-        return str;
+    return 1; // String is Palindrome
 }