#include <iostream>
#include <string>
 
using namespace std;
 
int main() {
 
  string user_input {}, pyra {""};
 
  cout << "Please enter a sequence of characters... ";
  cin >> user_input;
  cout<<endl; 
  string space (user_input.length() - 1, ' ');   // create it here !!
 
  for (size_t i{0}; i < user_input.length(); ++i) {
    pyra = user_input.substr(0, i+1 );  
 
    cout << space << pyra;
 
       for (auto j {pyra.length()}; j > 0; --j) {
        cout << pyra.at(j-1);   // don't go out of bounds
      }
    space.erase(0, 1);
    cout << endl;
  }
  return 0;
}

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