Reverse String Not functioning properly

You can easily fix your original code by changing 1 line of code

This is the WRONG code (Original Code) :

reverse[i]= name[count-i-1]; // WRONG -- ORIGINAL code inside the for loop

This is the CORRECT code (New Code):

reverse += name[count-i-1]; // CORRECT code

Here is the full and correct code:

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

int main(){
  string name = "dog";
  string reverse;
  int count = name.length();
 for (int i=0;i<count;i++){
    reverse += name[count-i-1];  // I fixed it here. It works now.
    cout<<reverse[i]<<endl;
 }
  cout<<reverse<<endl;
  return 0;
}

I have tested and verified that it works now.

The string reverse is 0 characters long so when you try assigning characters to it using operator[], you write out of bounds, making your program have undefined behavior.

One way to solve the problem is to create it with the same length as name:

string reverse(name.size(),' ');

or, to instead leave it as is, and add characters to it:

string reverse;
reverse.reserve(name.size()); // reserve space (may make it a little faster)

for (int i=0;i<count;i++){
    reverse.emplace_back(name[count-i-1]); // or push_back
}

Another option could be to use std::copy and copy it in reverse using the std::strings reverse iterators:

#include <algorithm>
#include <iterator>

std::copy(name.rbegin(), name.rend(), std::back_inserter(reverse));

or, if you don't need to keep the original content in name, you could reverse it directly:

#include <algorithm>

std::reverse(name.begin(), name.end()); // reverses name itself

You want to set up your forLoop backwards. Do for( int i = ( count-1 ) ; i >= 0 ; i-- ){...}

Edit: initialize reverse to "" and simplify the inside of the new for loop to be reverse = ( reverse + name.at(i) ) ; and only do the final cout after the loop finishes (get rid of the inside one)