i dint get the code

[yashshringare]

char[] arr = input.toCharArray();

char Operator = arr[1];
double num1 = (double)(arr[0]-'0');
double num2 = (double)(arr[2]-'0');

why do we use -'0' in the above code can you please explain

[Himanshu7901]

it is the way to write any method.