libc++abi.dylib: terminate called throwing an exception Abort trap: 6

Question

I am writing a code to find palindromic numbers. I am using this to also learn how to code and this is the code I have written:

#include <iostream>
#include <sstream>
using namespace std;

bool IsPalindromic (int n) {
    int I;
    string Number; //Starting to convert integer to string
    ostringstream convert;
    convert << n;
    Number = convert.str(); //Conversion is complete
    int M = Number.length();
    bool Result = true;
    if (M % 2 == 0)
        I = M / 2;
    else
        I = (M - 1)/2;
    for (int i = 1; i <= I; i++) {
        if (Number.at(i) != Number.at(M-i+1))
            Result = false;
    }
    return Result;
}

int main(int argc, char *argv[]) {
int num;
cout << "Enter an integer:";
    cin >> num;
    cout << IsPalindromic(num) << endl;
    return 0;
}

But when I try to run it and enter an integer as an input, I get the following error:

libc++abi.dylib: terminate called throwing an exception 
Abort trap: 6

I can't find any error in logic of the code. Can you help me with identifying the problem? I am compiling using g++ on Mac OSX 10.8.4

Solution

In the line:

if (Number.at(i) != Number.at(M-i+1))

when i = 1 you try to access Number.at(M) which is out of the bounds of string M while M is the length of the string. Rather, it should be:

if (Number.at(i) != Number.at(M-i))

Comments

[oxtay]

So that means the characters in a string start at 0 and go to M-1. Thanks!

[juanchopanza]

@user2613064 not only in strings. In arrays and all standard library containers.