Page 379 - Programming Microcontrollers in C

364 Chapter 7 Advanced Topics

to zero and bit is given the value bitbase. Then the code for
each character is retrieved successively. If the character read is a
space, the first entry in the table is used; if it is a new line character,
the second entry in the table is used; and if it is any other letter, the
letter is converted to an index into the alphabet and that particular
code, offset by two, is used as the code string for the input character.
static char *code[]={
“100”,“101”,”0001",”0000111",”000010",”111110",
”01",“0000110110”,”000011000",”000001",”1100",
”000011001",“1111111”,”1110",”111100",”1101",
”0011",”111111001",“11111101111”,”0010",”111101",
”000000",”111111000",“111111010”,”0000110111",
”11111101110",”000011010",“1111110110”
};

#include <ctype.h>
int encode(char *a,unsigned *array,int length)
{
unsigned i,bit,bitbase=~(~0u>>1);
int c=1;
char *ptr,*pa;

pa=a;
for(i=0;i<length;i++)
array[i]=0; /* initialize the array */
i=0;
bit=bitbase;
while(c!=’\n’)
{
c=*pa++; /* assumes file is not empty */
if(isalpha(c=toupper(c))||c==’ ‘||c==’\n’)
{
if(c==’ ‘)
ptr=code[0];
else if(c==’\n’)
ptr=code[1];
else
ptr=code[c-’A’+2];