Learn to Program with C_ Learn to Program using the Popular C Programming Language ( PDFDrive )

Chapter 2 ■ C – The Basics
token
int
main
Starting from the beginning, we can list the tokens in order:
type
reserved word
identifier
( left bracket, delimiter
) right bracket,
delimiter
{ left brace, delimiter
int reserved word
a identifier
, comma, delimiter
b identifier
, comma, delimiter
sum identifier
; semicolon, delimiter
a identifier
= equals sign, delimiter
14 constant
; semicolon, delimiter
And so on. Therefore we can think of a program as a stream of tokens, which is precisely how
the compiler views it. So that, as far as the compiler is concerned, the above could have been
written like this:
int main() { int a, b, sum;
a = 14; b = 25; sum = a + b;
printf("%d + %d = %d\n", a, b, sum); }
The order of the tokens is exactly the same; to the compiler, it is the same program. To the
computer, only the order of the tokens is important. However, layout and spacing are important to
make the program more readable to human beings.
2.3.1 Spacing Within a Program
Generally speaking, C programs can be written using “free format.” The language does not require
us, for instance, to write one statement on a line. Even a simple statement like
a = 14;
25
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