C＃编程分配

Question

The teacher wants me to create 2 files & insert random characters inside. Both files should be the same length. In one file a keyword "Hello" should be inserted randomly.

I did this for the first file:

var stringChars = new char[100];
var random = new Random();
var chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";


for (int i = 0; i < stringChars.Length; i++)
{
    stringChars[i] = chars[random.Next(chars.Length)];

}

I did this for the second file:

   var stringChars2 = new char[100];
   var random2 = new Random();
   var chars2 = "ABCDEFGHIJKLMNOPQRSTUVWXYZxxxxx";

   for (int i = 0; i < stringChars2.Length; i++)
   {
       stringChars2[i] = chars2[random2.Next(chars2.Length)];

   }


   string string2 = new string(stringChars2);
   string2 = string2.Replace("x", "\"Hello\"");

My problem is I don't know how to make the length of both files equal with the string replace trick. The second file will always be longer.

Answer 1

Here's an object oriented approach. I emphasize this approach since you have to perform similar operations multiple times (two). Thus, you shouldn't repeat yourself (google DRY prinicpal).

I won't tell you how to use these methods, you can figure that our for yourself:

public static class StringManipulation
{
    public static string GetXRandomCharacters(int x)
    {
        System.Text.StringBuilder sb = new System.Text.StringBuilder();
        var random = new Random();
        var chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

        for (int i = 0; i < stringChars.Length; i++)
        {
            sb.Append(chars[random.Next(chars.Length)]);
        }

        return sb;
    }

    public static string InjectWordAtRandom(string str, string word)
    {
        var random = new Random();
        int start = random.Next(str.Length - word.Length);

        str.Remove(start, word.Length).Insert(start, word);
    }
}

Hint: I have provided static methods but you don't have to do it that way. Try removing static from the method headers and creating an instance of the class to access it's properties.