Adding letters to arrays??

[mustachMan]

I am trying out these little crack the code programs and at one point there is a function that adds letter to the array then gets the modulo? i have no idea what it is doing.

char strarr[] = guess.toCharArray();
		for (int i=0; i<strarr.length; i++) 
		{
			strarr[i] = (char)((strarr[i]-'A'+9)%26+'A');
		}

the array is : "CQXVJBSNOONABXW"

[al_Marshy_1981]

ascii value of 'A'=65(decimal). 65+9=74.

so say the guess was 'a' which is equal to 97 in decimal. That would leave you
with 97-65+9=41.
41%26=15;
15+'A' = 15+ 65 = 80;

80 in ascii = P capital.

have a look here: Ascii Table - ASCII character codes and html, octal, hex and decimal chart conversion

[alacn]

tbh looks like very basic encryption