smallest palindrome c++

#include <iostream>
#include<string>
#include<strings.h>
#include<vector>
#include<sstream>
using namespace std;
void nextSmallestPalindrome(string inputString)
{
    int length = inputString.length();
    string compString = "";
    string finalString = "";
    stringstream ss;
    int j=0,i=0;
    //if the number is less than 9 then the smallest palindrome is 11
    if(length == 1 && inputString < "9") {
        cout<<"The next smallest palindrome is : 11";
    }
    for (int k=0; k<length;k++){
        compString += "9";
    }

    //case 1 if the input string contains all 9's
    if(inputString == compString) {
        for (int k=0; k<length-1;k++) {
            finalString += "0";
        }
        finalString = "1" + finalString + "1";
        cout<<"The next smallest palindrome is : "<<finalString;
    }
        //if the input string contains digits other than 9
    else {
        //convert string to vector to make it easy for manipulation
        vector<int> myStr;
        for(unsigned int k=0; k<inputString.length(); k++) {
            myStr.push_back((int) (inputString[k]-48));
        }

        //calculating mid positions
        if (length%2 == 0) {
            i = int(length/2) - 1;
            j = i+1;
        }
        else {
            i = int(length/2) - 1;
            j = i+2;
        }

        //checking if the entered string is already a palindrome
        bool alreadyPalindrome = true;
        int t1 = i,t2 = j;
        while(t1>-1) {
            if(myStr[t1] != myStr[t2]) {
                alreadyPalindrome = false;
                break;
            }
            t1 -=1;
            t2 +=1;
        }

        if(alreadyPalindrome){
            if(length%2 == 0){
                if(myStr[i]!=9 && myStr[j]!= 9){
                    myStr[i] += 1;
                    myStr[j] +=1;
                }
                else{
                    while(myStr[i] == 9){
                        myStr[i] = 0;
                        myStr[j] = 0;
                        i -= 1;
                        j += 1;
                    }
                    myStr[i] += 1;
                    myStr[j] += 1;
                }
                for(unsigned int k=0; k<myStr.size(); k++)
                {
                    ss << myStr[k];
                }
                finalString = ss.str();
                //ss.clear();
                cout<<"The next smallest palindrome is : "<<finalString;
            }
            else{
                int t1 = length/2;
                if(myStr[t1] == 9){
                    myStr[t1] = 0;
                    while(myStr[i] == 9){
                        myStr[i] = 0;
                        myStr[j] = 0;
                        i -= 1;
                        j += 1;
                    }
                    myStr[i] += 1;
                    myStr[j] += 1;
                }
                else{
                    myStr[t1] += 1;
                }
                for(unsigned int k=0; k<myStr.size(); k++)
                {
                    ss << myStr[k];
                }
                finalString = ss.str();
                //ss.clear();
                cout<<"The next smallest palindrome is : "<<finalString;
            }
        }
        // if the string is not already a palindrome
        else {
            //starting from middle leave all the digits that are same on both sides
            while(myStr[i] == myStr[j]){
                i -= 1;
                j += 1;
            }
            //if the number on the left side is greater than the number on the right side
            // then copy the left side to right side
            if(myStr[i] > myStr[j]){
                while(i > -1){
                    myStr[j] = myStr[i];
                    i -= 1;
                    j += 1;
                }
                for(int k=0; k < myStr.size(); k++){
                    ss<<myStr[k];
                }
                finalString = ss.str();
                cout<<"The next smallest palindrome is : "<<finalString;
            }
            // if the number on the left is less than the number on the right
            // then increment all the numbers between i and j
            // then if i+1 == j then increment ith element  and copy it to jth element
            // then copy the remaining left side to right side
            else{
                //then increment all the numbers between i and j
                for(int k=i+1; k < j ; k++){
                    myStr[k] +=1;
                }

                if(i+1 == j){
                    myStr[i] += 1;
                    myStr[j] = myStr[i];
                    i -= 1;
                    j += 1;
                }

                while(i > -1){
                    myStr[j] = myStr[i];
                    i -= 1;
                    j += 1;
                }
                for(int k=0; k < myStr.size(); k++){
                    ss<<myStr[k];
                }
                finalString = ss.str();
                cout<<"\nThe next smallest palindrome is : "<<finalString;
            }
        }
    }
}
int main()
{
    string inputString;
    int temp;
    bool cont = true;
    while(cont){
        cout << "Enter the number : ";
        cin>>inputString;
        nextSmallestPalindrome(inputString);
        cout<<"\nDo you want to continue (1/0) : "<<endl;
        cin>>temp;
        if(temp == 0){
            cont = false;
        }
    }

    return 0;
}