User manual

258
mikoC PRO for dsPIC
MikroElektronika
Compound Statements (Blocks)
The compound statement, or block, is a list (possibly empty) of statements enclosed in matching braces { }.
Syntactically, the block can be considered to be a single statement, but it also plays a role in the scoping of identiers.
An identier declared within the block has a scope starting at the point of declaration and ending at the closing brace.
Blocks can be nested to any depth up to the limits of memory.
For example, the for loop expects one statement in its body, so we can pass it a compound statement:
for (i = 0; i < n; i++ ) {
int temp = a[i];
a[i] = b[i];
b[i] = temp;
}
Note that, unlike other statements, compound statements do not end with semicolon (;), i.e. there is never a semicolon
following the closing brace.
Preprocessor
Preprocessor is an integrated text processor which prepares the source code for compiling. Preprocessor allows:
- inserting text from a specifed le to a certain point in the code (see File Inclusion),
- replacing specic lexical symbols with other symbols (see Macros),
- conditional compiling which conditionally includes or omits parts of the code (see Conditional Compilation).
Note that preprocessor analyzes text at token level, not at individual character level. Preprocessor is controled by
means of preprocessor directives and preprocessor operators.
Preprocessor Directives
Any line in the source code with a leading # is taken as a preprocessing directive (or control line), unless # is within
a string literal, in a character constant, or embedded in a comment. The initial # can be preceded or followed by a
whitespace (excluding new lines).
A null directive consists of a line containing the single character #. This line is always ignored.
Preprocessor directives are usually placed at the beginning of the source code, but they can legally appear at any point
in a program. The mikroC PRO for dsPIC30/33 and PIC24 preprocessor detects preprocessor directives and parses the
tokens embedded in them. A directive is in effect from its declaration to the end of the program le.
Here is one commonly used directive:
#include <math.h>