Help on a C program....

Question

i'm trying to write an appendString function to stick two strings together, and I'm lost....
it's supposed to be a combination of a C & pascal string with values at the beginning to signify length & a terminating null
typedef char* String;
int lengthString(String self) {
     int k = -1; // start at self[-1] and keep going left from there
     int length = 0;
     while (self[k] == MAX_CHAR) {
          length += MAX_CHAR;
          k = k - 1;
     return self[k] + length;
void appendString(String* self, String suffix) {
     int k = 0;
     int length = lengthString(*self) + lengthString(suffix);
     int offset = 1 + (length / MAX_CHAR);
     String combo = (String) malloc(offset + length + 1);
     combo[0] = length % MAX_CHAR;
     combo = combo + offset;
     if (offset > 1)
          for (int i = 1; i < offset; i++)
               combo[0-i] = MAX_CHAR;
     for (k = 0; (*self)[k] != 0; k++)
          combo[k] = (*self)[k];
     for (int i = 0; suffix[i] != 0; i++, k++)
          combo[k] = suffix;
     combo[k] = 0;
     destroyString(*self);
     destroyString(suffix);
     *self = combo;
void destroyString(String self) {
     int offset = -1;
     while (self[offset] == MAX_CHAR)
          offset--;
     self = self + (char)offset;
     free(self);

Answer 1

weel try this, sorry if I wrong, i don't use C a long time
char* strcat(char *str1, char *str2)
    char *result;
    while(*str1){
       (*result) = (*str1);
       result++;
       str1++;
     while(*str2){
       (*result) = (*str2);
        result++;
        str2++;
     return result;
}