error: invalid conversion from 'char' to 'const char*' in palindrome program - c++

Question

This code is an attempt to test whether or not a string is a palindrome. It reads a string of characters, pushing each character onto a stack as it is read and simultaneously adding it to a queue. Then, it uses basic stack and queue operations to determine if the string is a palindrome.
The program blows up with the aforementioned error(s) when it hits:
inStack.push(inString[i]);
inQueue.push(inString[i]);
and I don't understand why, or how to fix it. The research I have done looking into this error as it applies to my case hasn't been fruitful. I'm fairly new to c++ so forgive me if I'm overlooking something stupid.
The code is as follows:
#include <iostream>
#include <stack>
#include <queue>
#include <string>
using namespace std;
int main()
{
stack <string> inStack;
queue <string> inQueue;
string inString; //user input
int inLength; //loop counter variable
bool isPalindrome(false);
cout<<"Enter a word to see if it is a palindrome: ";
cin>>inString;
if (inString.size() > 0)
{
for (int i = 0; i <= inLength; i++)
{
inStack.push(inString[i]); //put string chars onto stack
inQueue.push(inString[i]); //add string chars to queue
}
isPalindrome = true;
while (isPalindrome && (!inStack.empty()) && (!inQueue.empty()))
{
if (inStack.top() != inQueue.front())
{
isPalindrome = false;
}
else
{
inStack.pop();
inQueue.pop();
}
}
}
if(isPalindrome == false)
{
cout<<"It is not a palindrome."<<endl;
}
else
{
cout<<"It is indeed a palindrome."<<endl;
}
return 0;
}

Answer 1

There are three main errors in your code.
You are pushing characters onto a stack and a queue that are defined to hold strings. The string constructor cannot implicitly convert from char to string, since there is no constructor that takes a char. You probably meant to define them as:
stack<char> inStack;
queue<char> inQueue;
You didn't set inLength; I suggest adding something like
inLength = inString.size();
after your if (inString.size() > 0) { to fix that.
Most important, you use i <= inLength (in your for loop condition), which won't work; you should use <, since pushing inString[inString.size()] is actually pushing one character beyond what you enter, which will always result in isPalindrome == false since your stack and queue will have an invalid (random garbage) character at the corresponding top and front.
These three changes appear to be enough to fix your project.
A simpler solution to give you an example of how C++ iterators can be used to reduce the amount of code you have to write for these kinds of things:
#include <iostream>
#include <string>
#include <vector>
using namespace std;
int main()
{
vector<char> left, right; // left-to-right and right-to-left lists
cout<<"Enter a word to see if it is a palindrome: ";
string inString; //user input
cin>>inString;
if(!inString.empty()){
// add characters left to right
left.insert(left.end(), inString.begin(), inString.end());
// add characters in reverse order, right to left
right.insert(right.end(), inString.rbegin(), inString.rend());
// compare the two vectors
if(left == right)
cout<<"It is indeed a palindrome."<<endl;
else
cout<<"It is not a palindrome."<<endl;
}
}

Answer 2

You forgot to assign to inLength the actual length of the string and get a outside i gets very big, bigger than it should be and you probably get a segmentation fault.
Try after reading the string to assign the value properly.
inLength = inString.size();
I hope this helps you.