Code for Run Length Encoding

Algorithm:

step 1: input string s, char *c
step 2: c = s;
step 3: foreach character *c, in the string s,
step 4: compare subsequent characters *p, if equal, inc counter till *p != *c
step 5: append c and count to enc_string
step 6: reset count to 1
step 7: make c = p;
step 8: end for

Program:

char* encode(char *s) {
 char *c, *p; char enc[100]; int count = 1, i = 0;
 if( s == NULL ) 
  return NULL;
 c = s;


 while( *c ) {
  if( !(*(c+1) ) { //end of string, append c and count
   enc[i++] = c;
   enc[i++] = count;
   count = 1;
   break;
  }
  p = c+1;
  
  while( *p == *c ) {
   p++;
   count++;
  }
  enc[i++] = c;
  enc[i++] = count;
  count = 1;
  c = p;
 }
 return enc;
}