1. Programming Paradigms
The C Programming Language

2. Components of a C Program
A C program is a collection of function definitions, (global) variable definitions, declarations and compiler directives
Functions ( e.g., void push( char c ) { … } )
Variables ( e.g., int top; char Store[MAX]; )
Declarations ( e.g., void push( char c ); )
Compiler directives ( e.g., #define MAX 100 #include <stdio.h> )
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

3. Built-in Data Types in C
int, char, float
Short and long versions of these data types
short, long, double, long double, …
No explicit boolean type in C
Control structures that require conditions expect an int value
0 => false, non-zero => true
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

4. Composite Types Arrays Structures
Collection of elements of the same type
Declaration: type varname[integer-value];
Structures
Collection of elements of different types or with different names
Declaration: struct strname { field declarations… }; struct strname varname;
dot operator: varname.field
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

5. Pointers Address operator: & De-referencing operator: *
Pointers and arrays
Array names as addresses
Pointer arithmetic
Array access []
Dynamic allocation
malloc, free, NULL
Multi-dimensional arrays
Pointers and structures: the -> operator
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

6. Strings String: sequence of characters (stored in a character array)
The null (‘\0’) terminator
String literals ( e.g., “hello” )
String functions (<string.h>)
strcpy
strlen
strcmp
strcat …
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

7. Statements expression-statement Block or compound-statement
Expression followed by a semicolon
expr; where expr consists of variables, constants, operators, parentheses, function calls
Block or compound-statement
0 or more statements enclosed in { }
Declarations may precede statements { decl decl decl … stmt stmt stmt }
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

8. Statements (decision)
if-statement
Condition bounded by parentheses
Numeric expression expected in condition
Optional else clause
switch-statement
Can be viewed as a special kind of block
Has entry points (through the case labels) and exit points (through break; statements )
switch expression should be of ordinal type
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

9. Statements (loops) while-statement do-while-statement for-statement
Loop test at the beginning of the loop
Loop body may not be executed at all
do-while-statement
Loop test at the end of the loop
Loop body executed at least once
for-statement
for( expr1; expr2; expr3 ) stmt
Has an equivalent while-loop formulation
Used if there is an explicit loop control variable
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

10. Statements (others) break; continue; return-statement
Breaks out of the nearest enclosing loop or switch
continue;
Proceeds to the loop test
return-statement
return expr;
Provides value return by a function
Without expr (if return type is void), the statement simply causes control to be returned to the caller
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

11. Functions Function definition: Return type Name Parameters
Body (block)
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

12. Parameter Passing In C, all parameters are pass by value
Pointers and the address operator enable a function to update data outside of the function
But the parameter passed (the address) is still a value
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.

13. Library Functions The C standard library
I/O, math, string functions and others
Prototypes are in:
<stdio.h>
<math.h>
<string.h>
<stdlib.h> …
6/15/2005
Copyright 2005, by the authors of these slides, and Ateneo de Manila University. All rights reserved.