If i want to alphabetizes a list of strings using a sorting algorithm and string comparison functions, do i have to use an array of pointers to achieve this? Since i have to sort the array subscripts first and then swap the elements ( which are strings ) if i'm using bubblesort?
Hope i explained clear.
thnx in advance
An array of pointers-to-chars would probably work the best (ie: the easiest).
Quzah.
Hope is the first step on the road to disappointment.
any Other alternatives? Coz i always like to know things done the other way.
thnx quzah
the above reply was mine, forgot to log in...
I suppose you could use a multidimensional array, and copy the data from one array cell to another. You also could use a linked list of strings, and order the list. There's probably a few other ways to do this.
Quzah.
Hope is the first step on the road to disappointment.
also, can i ONLY use bubblesort since i can only compare two strings at a time with strcmp() ?
thnx
This really isn't that tough. Here's how I strongly reccomend doing this...
1) Write a function that bubble sorts an array of ints.
2) Change the array type from int [] to char * []
3) The temp value you use to swap two values, change it to a char *
4) The line that goes something like...
if (array[i] < array[i + 1])
Change from using the < to using strcmp.
There is practically no difference between bubble sorting ints and strings, or anything really.
Callou collei we'll code the way
Of prime numbers and pings!
And no, practically all sorting methods involve comparing two elements at a time, although bubble sort is really one of the easiest to implement.
Callou collei we'll code the way
Of prime numbers and pings!
*sigh*
;Code:#include <stdlib.h> #include <string.h> int main(void) { char *char_array[255]; ///some stuff qsort(char_array, 0, strlen(char_array), (int(*)(const void *, const void *))strcmp); //more code return 0; }
can i hav the source code for quickSort pls?
thnx mastr and questionC
Code:#include<stdio.h> #include<stdlib.h> #include<string.h> int IsLess(char * x, char * mid) { //control the order of alphebetizing here with < or > if(strcmp( x,mid) < 0) return -1; else return 1; } char * GetRecord(char * a[], int x) { char * temp = (char*) malloc (sizeof(char) * 20); temp = a[x]; return temp; } void QSort(char * a[], int left, int right) { int i = left; int j = right; char * temp = NULL; //frees placeholder during recursive call free(temp); //get middle record temp = GetRecord(a, (i+j) / 2); do { while (IsLess(GetRecord(a,i), temp) < 0 && i < right) i++; while (IsLess(temp,GetRecord(a,j)) < 0 && j > left) j--; //swap if( i <= j) { temp = a[i]; a[i] = a[j]; a[j] = temp; i++; j--; } }while( i <= j); //recursive calls if(left < j) QSort(a,left,j); if(i < right) QSort(a,i,right); } int main() { int i; const int size = 5; //jagged array rather than a smooth array[x][size] char * array[size] = {"namev","namee","namex","namea","namen" }; QSort(array, 0, size - 1); printf("Sorted array of strings.\n"); for(i = 0; i < size; i++) { printf("%s\n",array[i]); } return 0; }
Last edited by Troll_King; 01-22-2002 at 08:34 AM.
ok, any way to do it WITHOUT using an array of pointers. As i say, i want to know two ways of doing things. If there isn't, then thats ok then.
TO QuestionC, your way only applies to alphatizing a list of characters right? How can you just change the array from type int to char? And what will be the result of that?
thnx
