sorting letters in a string with double pointer - c

Question

I'm stuck with sorting letters in a string. It must be sorted in alphabetical order using double pointers.
#define SIZE 21 //defined index of the array
int _tmain(int argc, _TCHAR* argv[])
{
// an array with 21 strings
char * string[SIZE] = { "dfghgfd", "rtyukljgfds", "sdsf", "fdgdfhg", "fgfhgjghj", "nmjlkjlk", "qwasazx",
"zxdfd", "opiljkg", "vcxdfgfd", "fgfhgfhgh", "bvvh", "bb", "dfsdretr",
"reuio", "cvbmhg", "fgfdyrtyty", "fgdgdfgdfgdf", "g", "fgdfg", "ghghgfhv" };
-----------------------Access to each string in array ------------------------
int Anz, i; //Anz - 21 strings
//declared new array
char** new_string;
new_string = (char**)malloc(sizeof(string));
Anz = sizeof(string) / sizeof(char*);
for (i = 0; i < Anz; i++)
{
new_string[i] = (char*)malloc(strlen(string[i]) + 1);
strcpy(new_string[i], string[i]);
}
----------------------- sorting letters--------------------------------------
char* temp;
int k, j;
for (k = 0; k<Anz - 1; k++)
{
for (j = k + 1; j<Anz; j++)
{
if (new_string[k] > new_string[j])
{
temp = new_string[k];
new_string[k] = new_string[j];
new_string[j] = temp;
}
}
}
return 0;
}

Answer 1

Not sure why you need the "a" array, since you can swap the characters using the new string array. Also, using a char * to hold the length of values is sort weird but I guess it works since the string lengths are pretty short.

Answer 2

Not sure if you wanted to sort the letters or the words. A commented section sorts the words.
Check the return of malloc as it can fail.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZE 21 //defined index of the array
int main(int argc, char** argv)
{
// an array with 21 strings
char * string[SIZE] = { "dfghgfd", "rtyukljgfds", "sdsf", "fdgdfhg", "fgfhgjghj", "nmjlkjlk", "qwasazx",
"zxdfd", "opiljkg", "vcxdfgfd", "fgfhgfhgh", "bvvh", "bb", "dfsdretr",
"reuio", "cvbmhg", "fgfdyrtyty", "fgdgdfgdfgdf", "g", "fgdfg", "ghghgfhv" };
int Anz, i; //Anz - 21 strings
int width = 0, len = 0;
//declared new array
char** new_string;
Anz = sizeof(string) / sizeof(*string);
if ( NULL == ( new_string = malloc ( Anz * sizeof( *new_string)))) {
fprintf ( stderr, "malloc failed\n");
return 0;
}
for (i = 0; i < Anz; i++)
{
len = strlen ( string[i]) + 1;
if ( len > width) {
width = len;//used later when printing
}
if ( NULL == ( new_string [i] = malloc ( width))) {
fprintf ( stderr, "[i] malloc failed\n");
//free memory allocated
while ( i) {
i--;
free ( new_string[i]);
}
free ( new_string);
return 0;
}
strcpy(new_string[i], string[i]);
}
/*
//sort words
int word = 0;
while ( word < Anz - 1) {
int end = word;
int temp = end + 1;
while ( end >= 0 && 0 > strcmp ( new_string[temp], new_string[end])) {
char *hold = new_string[temp];
new_string[temp] = new_string[end];
new_string[end] = hold;
end--;
temp--;
}
word++;
}
word = 0;
while ( word < Anz) {
printf ( "Anz[%2d] is %s\n", word, new_string[word]);
word++;
}
*/
//sort letters in word
char swap;
int sorted;
int prior;
int each;
int start;
word = 0;
while ( word < Anz)
{
start = 0;//new_string[Anz][0]
sorted = start;
prior = start;
each = start + 1;//new_string[Anz][1]
printf ( "Anz[%2d] is %-*s", word, width, new_string[word]);
while ( '\0' != new_string[word][each]) {
while ( prior >= 0 && new_string[word][each] < new_string[word][prior]) {
swap = new_string[word][each];
new_string[word][each] = new_string[word][prior];
new_string[word][prior] = swap;
each--;//move toward start of string
prior--;
}
sorted++;//move toward end of string
prior = sorted;
each = prior + 1;
}
printf ( " sorted %s\n", new_string[word]);
word++;
}
//release allocated memory
word = 0;
while ( word < Anz) {
free ( new_string[word]);
word++;
}
free ( new_string);
return 0;
}