Create Nearest Palindrome.cpp

Nearest Palindrome.cpp

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+// C++ Program to find the closest Palindrome
+// number
+#include <bits/stdc++.h>
+using namespace std;
+
+// function check Palindrome
+bool isPalindrome(string n)
+{
+    for (int i = 0; i < n.size() / 2; i++)
+        if (n[i] != n[n.size() - 1 - i])
+            return false;
+    return true;
+}
+
+// convert number into String
+string convertNumIntoString(int num)
+{
+
+    // base case:
+    if (num == 0)
+        return "0";
+
+    string Snum = "";
+    while (num > 0) {
+        Snum += (num % 10 - '0');
+        num /= 10;
+    }
+    return Snum;
+}
+
+// function return closest Palindrome number
+int closestPalindrome(int num)
+{
+
+    // case1 : largest palindrome number
+    // which is smaller to given number
+    int RPNum = num - 1;
+
+    while (!isPalindrome(convertNumIntoString(abs(RPNum))))
+        RPNum--;
+
+    // Case 2 : smallest palindrome number
+    // which is greater than given number
+    int SPNum = num + 1;
+
+    while (!isPalindrome(convertNumIntoString(SPNum)))
+        SPNum++;
+
+    // check absolute difference
+    if (abs(num - RPNum) > abs(num - SPNum))
+        return SPNum;
+    else
+        return RPNum;
+}
+
+// Driver program to test above function
+int main()
+{
+    int num = 121;
+    cout << closestPalindrome(num) << endl;
+    return 0;
+}