sort function won't print sorted array? - c

Question

My sort function won't print the sorted array?
I'm trying to write a program that gathers array elements, sorts the array, then prints the factorial of each element. I don't want to get ahead of myself and write the recursive function if the array isn't being sorted correctly. The sort seems fine to me; people have criticized me using while loop but I don't know another way yet. Any input is appreciated.
#include <stdio.h>
int sorter(int numbList[]);
int getData(int numList[]);
//int recursive(int numList[]);
int main(void) {
int x;
int numberList[x];
getData(&numberList[x]);
sorter(&numberList[x]);
//recursive(&numberList[x]);
return 0;
}
//gets user input-data
int getData(int numbList[]) {
int i;
int x;
printf("Enter number of Elements:\n");
scanf("%d", &x);
printf("Enter the values for each element starting from first
element:\n");
for (i = 0; i < x; i++) {
scanf("%d", &numbList[i]);
}
printf("\nYou have filled the array list with\n");
for (i = 0; i < x; i++) {
printf("%d\n", numbList[i]);
}
return numbList[x];
}
//sorter function
int sorter(int numbList[]) {
int x;
int temp;
int swapped;
while (1) {
swapped = 0;
for (int i = 0; i < x; i++) {
if (i > numbList[i + 1]) {
temp = numbList[x];
numbList[x] = numbList[x + 1];
numbList[x + 1] = numbList[x];
swapped = 1;
}
if (swapped == 0) {
break;
}
}
printf("Array as sorted:\n");
for (int i = 0; i < x; i++) {
printf("%d\t", numbList[x]);
}
return(numbList[x]);
}
}
//recursive factorial function
/* int recursive(int numbList[]) {
int b = 0;
numbList[b] *= numbList[b - 1];
return 0;
} */

Answer 1

Some hints as comments in your code:
It still won't do the job, but get you in better shape...
int main(void)
{
//uninitialized x!
int x;
//Even if you get a value for x, VLAs are depreciated
int numberList[x];
//Both calls get the adress of last value + 1 in numberList.
//So you a) go out of the array bounds, and b) why would you want
//the last element's address??
//Just use it like getData(numberList);
getData(&numberList[x]);
sorter(&numberList[x]);
return 0;
}
//gets user input-data
//What is the return value for?
int getData(int numbList[])
{
int i;
int x;
printf("Enter number of Elements:\n");
scanf("%d",&x);
printf("Enter the values for each element starting from first element:\n");
for(i=0;i<x;i++){
scanf("%d",&numbList[i]);
}
printf("\nYou have filled the array list with\n");
for(i=0;i<x;i++){
printf("%d\n",numbList[i]);
}
//see above
return numbList[x];
}
//sorter function
//Again, what and why return?
int sorter(int numbList[])
{
//uninitialized x!
int x;
int temp;
int swapped;
while(1)
{
swapped=0;
for(int i=0;i<x;i++)
{
//What do you compare here? Think.
if(i>numbList[i+1])
{
temp=numbList[x];
numbList[x]=numbList[x+1];
//What do you have temp for??
numbList[x+1]=numbList[x];
swapped=1;
}
//Pretty sure you want an else clause here
if(swapped==0)
{
break;
}
}
printf("Array as sorted:\n");
for(int i=0;i<x;i++)
{
printf("%d\t",numbList[x]);
}
return(numbList[x]);
}
}

Answer 2

There are multiple problems in your code:
the number of elements x is uninitialized when you define the array numbList[x]. This has undefined behavior. You should pass a pointer to the count to getData and this function should update this value, allocate the array, read the values and return a pointer to the array.
You should not break strings on multiple lines without a \
The swap code is broken: the test if (i > numbList[i + 1]) is incorrect, it should be
if (numbList[i] > numbList[i + 1])
the swap code should use i instead of x as an index and the last assignment in the swap code should store temp into numbList[i + 1].
the inner loop should stop at x - 1 to avoid reading past the end of the array.
you should let the inner loop run to the end and break from the outer loop if swapped == 0.
Here is a corrected version:
#include <stdio.h>
#include <stdlib.h>
int *getData(int *count);
void sorter(int numList[], int count);
int main(void) {
int x;
int *numberList;
numberList = getData(&x);
if (numberList != NULL) {
printf("Elements entered:");
for (int i = 0; i < x; i++) {
printf(" %d", numberList[i]);
}
printf("\n");
sorter(numberList, x);
printf("Sorted array:");
for (int i = 0; i < x; i++) {
printf(" %d", numberList[i]);
}
printf("\n");
free(numberList);
}
return 0;
}
//gets user input-data
int *getData(int *countp) {
int i, x;
int *numbList;
printf("Enter the number of elements: ");
if (scanf("%d", &x) != 1 || x <= 0) {
printf("Invalid size:");
return NULL;
}
numbList = calloc(sizeof *numbList, x);
if (numbList == NULL) {
printf("Memory allocation error:");
return NULL;
}
printf("Enter the element values: ");
for (i = 0; i < x; i++) {
if (scanf("%d", &numbList[i]) != 1) {
free(numbList);
return NULL;
}
}
*countp = x;
return numbList;
}
//sorter function
void sorter(int numbList[], int x) {
for (;;) {
int swapped = 0;
for (int i = 0; i < x - 1; i++) {
if (numbList[i] > numbList[i + 1]) {
int temp = numbList[i];
numbList[i] = numbList[i + 1];
numbList[i + 1] = temp;
swapped = 1;
}
}
if (swapped == 0) {
break;
}
}
}

Answer 3

You can use bubble sort algorithm technique which is fast sorting algorithm and it uses for loop instead of while loop
int bubbleSorter(int numbList[])
{
int temp;
int i, x;
bool swapped = false;
for (i = 0; i < x - 1; i++)
{
swapped = false;
for (j = 0; j < x - 1 - i; j++)
{
if (list[j] > list[j + 1])
{
temp = list[j];
list[j] = list[j + 1];
list[j + 1] = temp;
swapped = true;
}
else {
swapped = false;
}
}
// if no number was swapped that means
// array is sorted now, break the loop.
if (!swapped) {
break;
}
printf("Array as sorted:\n");
for (int i = 0; i<x; i++)
{
printf("%d\t", numbList[x]);
}
return(numbList[x]);
}
}