Expressions, Variables and Assignments - A Concise and Practical Introduction to Programming Algorithms in Java - page 12

System . out . print ( "Total credit (in US dollars):\t" );
System . out . println (100+150) ;

System . out . print ( "Total debit (in US dollars):\t" );
System . out . println (50+25+100) ;

System . out . print ( "Balance:" );
}
}

Running this program, we get:
Total credit (in US dollars): 250

Total debit (in US dollars): 175

Note that the

t inside the string "Total credit (in US dollars):\t" denotes
the tabulation character that allows one to nicely align the latter numbers. The
problem is to get the balance we need to subtract 175 from 250. Of course, this
could be computed and displayed with the instruction:

\

System.out.println((100+150)-(50+25+100));

...but this will not yield an ecient approach since we would again compute the
two cumulative credit/debit sums. A much better strategy consists of storing
intermediate calculations in containers by using variables, as explained next.

1.6.1 Variables for storing intermediate values

In Java, variables are all typed . Java belongs to the large category of typed
programming languages. This means that we need to specify the type of
variables when declaring variables. To declare a variable named credit for
storing the overall credit modeled as an integer number, we use the syntax:

int credit;

Variables always need to be declared before use. By convention, we choose
in this textbook to declare all variables at the beginning of the main block
(delimited by the braces ). In this application, we consider that credit/debit

numbers are natural numbers (integers), so that we declare the variable to be
of type int .

{}

Program 1.8 Balance sheet using integer variables
class BalanceSheet2 {
public static void main ( String [ ] args )

int credit ;
int debit ;