Tiny C is a simple compiler which accepts code according to the following BNF:
<program> ::= <function>*
<function> ::= <identifier> <parameter list> <top level declaration>* <statement>*
<parameter list> ::= '(' <variable list> ')'
<top level declaration> ::= <variable list> ';'
<variable list> ::= <data type> <identifier> [',' <identifier>]* | <data type> <identifier> '[' <array size> ']'
<data type> ::= 'byte' | 'word'
<statement> ::= '{' <compound statement> '}' | <statement> ';'
<compound statement> ::= <statement>*
<statement> ::= <if statement> |
<while statement> |
<for statement> |
<read statement> |
<print statement> |
<assignment statement> |
<function call statement> |
<return statement> |
<null statement>
<if statement> ::= 'if' '(' <boolean expression> ')' <statement> ['else' <statement>]
<while statement> ::= 'while' '(' <boolean expression> ') ' <statement>
<for statement> ::= 'for' '(' identifier '=' <expression> 'to'
<expression> ')' <statement>
<read statement> ::= 'read' <identifier>
<print statement> :: 'print' <expression> | <string>
[',' <expression> | <string> ]*
<assignment statement> ::= <identifier> '=' <expression> ';'
<function call statement> ::= <identifier> '(' [<argument list>] ')' ';'
<argument list> ::= <identifier> [',' <identifier>]*
<return statement> ::= 'return' <expression> ';'
<null statement> ::= ';'
<boolean expression> ::= <relation> [<'|' | '&'> <relation>]*
<relation> ::= <expression> [<'>' | '<' | '=' | '>=' | '<=' > <expression>]
<expression> ::= <term> [<'+' | '-'> <term>]*
<term> = <factor> [<'*' | '/'> <factor>]*
<factor> = '(' <boolean expression> ')' | <number> | <identifier> | <'true' | 'false'>
To begin with, we’ll write the typical “hello world” program:
Go to the DOS command prompt and type in “edit hello.tc”. Now type in the following two lines of code:
Main()
Print(“hello, world”);
That’s it. Now compile the program by typing in the command “TCC hello.tc”. If everything is OK, you get the message “Compilation successful”. Now run the program “hello.exe”.
REM: Unlike C, Tiny C is not case sensitive.
Variables in Tiny C are declared the same ways as in C:
Byte counter, year = 2004;
Word numbers[5] = {647,7878,34,898,454};
REM: identifiers in Tiny C must be entirely alphabetic (so “last_year2” is not allowed) .
There are two data types in Tiny C:
- the “byte” is an integer containing values from 0 to 255
- the “word” is also an integer containing values from 0 to 65535
Arithmetic expressions in Tiny C are formed in exactly the same way as in C.
REM: All arithmetic is done unsigned. REM: Unlike C, there is no “%” operator.
Boolean expressions are also formed like in C, except that “||” = “|”, “&&” = “&” and “= =” = “=”:
year = 2004 & numbers[counter] = 13
You can choose among three different control constructs in Tiny C:
if(year = 2003 | year = 2004)
counter = counter + 1;
while(true)
;
for(counter = 0 to 4)
numbers[counter] = counter * 5;
##Functions
printArr(byte arr[],byte size)
byte counter;
{
for(counter = 0 to size – 1)
print(“the value of entry no ”,counter,“ is ” ,arr[counter],endl);
}
max(word numberA, word numberB)
if(numberA > numberB)
return numberA;
else
return numberB;
- REM: you don’t have to declare the return type of a function; it is always a “word”.
- REM: “print” is a standard library function, as is “read”:
factorial(byte b)
{
if(b = 0 | b = 1)
return 1;
else
return b * factorial(b-1);
}
selectionSort(word numbers[], word arraySize)
word i,j,min,temp;
{
for (i = 0 to arraySize-2)
{
min = i;
for (j = i+1 to arraySize-1)
{
if (numbers[j] < numbers[min])
min = j;
}
temp = numbers[i];
numbers[i] = numbers[min];
numbers[min] = temp;
}
}
printarr(word arr[],byte size)
byte i;
{
for(i = 0 to size-1)
{
print(arr[i],endl);
}
}
main()
byte b; byte counter = 4;word arr[5];
{
for(b = 0 to 4)
{
print("enter a value less than 65536:");
read(arr[b]);
}
selectionSort(arr,5);
print("the numbers sorted:",endl);
printarr(arr,5);
print("enter a number:");
read(b);
print("the factorial of b is ",factorial(b));
}
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