Need Help related to C++ Program

I am new to c++ programming. n my program I have to check the frequency of characters in the string but there is an issue. Whenever there are multiple same characters it first shows 1 and then 2 then 3.

#include <iostream>
using namespace std;

int main()
{

    cout << "Array Enteries Occurance Checker \n";
    int size_of_array = 20;
    char string_array[size_of_array]{};
    cout << "Please enter the string text : ";
    cin.getline(string_array, size_of_array);

    cout << "The Text Enter is : " << string_array << endl;

    int counter = 0;
    char character = 97;

    for (character = 97; character <= 122; character++) {
        counter = 0;
        for (int i = 0; string_array[i] != '\0'; i++) {
            if (string_array[i] == character) {
                counter++;
                cout << counter << " =  " << character << endl;
            }
        }
    }
    cout << endl;

    for (character = 65; character <= 90; character++) {
        for (int i = 0; i < size_of_array; i++) {
            if (string_array[i] == character) {
                counter++;
                cout << counter << " =  " << character << endl;
            }
        }
        counter = 0;
    }

    return 0;
}