java - Unable to correctly generate checksum -

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i trying calculate simple checksum , i'm doing checksum test.

public void readfile() {      byte counter = 0;     byte[] data = new byte[68];          while(x.hasnextint())     {         data[counter++] = (byte)x.nextint();         if(counter == 67)             break;      }      int sum = 0;     (int = 0; < 67; i++)         sum += (data[i] & 0xff);     system.out.println((int)(sum & 0xff)); //checksum      //perform checksum test.     data[counter] = (byte)(sum & 0xff);     sum = 0;     (int = 0; < 68; i++)         sum += (data[i] & 0xff);      system.out.println((int)(sum & 0xff)); //checksum test }

i reading first 67 integer values of file , saving them inside byte array. integers < 256. variable 'x' file reading. however, when perform checksum test, value outputted isn't 0. not able diagnose computing incorrectly.

i'm not sure you're trying do. first 67 characters, calculate checksum, , assume 67, plus checksum, 0. not. you're adding checksum, not subtracting it.

so if checksum not 0 or 128, end value twice checksum. right?


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