Serial comunication problem

I’m relatively new to Arduino, but I know this isn’t supposed to happen… I’m testing my serial because I was getting false inputs when I’d type a serial phrase… I set up this echo script from online sources and any time I type 1 it returns a 1 like it should but also a -38 on the next line immediately after… The -38 becomes 10 if I don’t include the subtraction

void setup()

void loop()
while (Serial.available() == 0);

int val = - ‘0’; /*<<<----- this subtraction changes the false value from -38 to 10 if it is not here. */

Arduino UNO R3
HP touchsmart TM2 running win7 64bit

ASCII "line-feed" (LF) character has the decimal value 10