使用嵌套的for循环将String数组中的每个String与一个用户输入字符串进行比较

Question

I am trying to compare two strings and sum the differences of their chars. One string is a user input (input) and the other is from an array of strings (binary_patterns_array).

I would like to compare each string in the array to the input and place the sum of their differences into another int array. I have another method that iterates through the int array to find the smallest value which will give me the index of closest matching pattern. Here's the code:

public static int[] difference(String input, String[] binary_patterns_array){
    int[] difference_array = new int[32];
    String  binary_pattern = "";
    int count = 0;
    for(int i = 0; i < binary_patterns_array.length; i++){
        binary_pattern = binary_patterns_array[i];
        for(int j = 0; j < input.length(); j++){
            if (binary_pattern.charAt(j) != input.charAt(j)){
                count += 1;
            }
         difference_array[i] = count;
        }
    }
    return difference_array;
}

This doesn't work but I'm not exactly sure why. The two loops do exactly what I want them to, but my if statement or the way i'm summing the differences isn't doing what I had hoped. Can anyone see any blatant mistakes? Thank you!

Answer 1

You need to reset count in every pattern iteration:

public static int[] difference(String input, String[] binary_patterns_array){
    int[] difference_array = new int[32];
    String  binary_pattern = "";
    for(int i = 0; i < binary_patterns_array.length; i++){
        int count = 0; // moved inside the loop so it is 0 at the beginning of each pattern
        binary_pattern = binary_patterns_array[i];
        for(int j = 0; j < input.length(); j++){
            if (binary_pattern.charAt(j) != input.charAt(j)){
                count += 1;
            }
        }
        difference_array[i] = count; // moved because it is cleaner outside the inner loop
    }
    return difference_array;
}

Answer 2

Multiple issues

1. count should be reset every time
2. Array size is hardcoded. It should be set as the size of binary_patterns_array
3. difference_array[i] should be set outside the inner loop.

4. No need to create temporary variable. It is just a memory overhead.

    public static int[] difference(String input, String[] binary_patterns_array) { int[] difference_array = new int[binary_patterns_array.length]; for (int i = 0; i < binary_patterns_array.length; i++) { int count = 0; for (int j = 0; j < input.length(); j++) { if (binary_patterns_array[i].charAt(j) != input.charAt(j)) { count++; } } difference_array[i] = count; } return difference_array; } 

Answer 3

Initialize count above inner loop and put difference_array[i] = count; out of inner loop.