sorting program using pointers - c

Question

I have a program that:
given a sequence of numbers,
sorts even numbers in ascending order, and
sort odd numbers in descending order, and
adds the sorted even numbers to an array followed by the sorted odd numbers.
Example:
Input: 1, 2, 3, 4, 5, 6
Expected output: 2, 4, 6, 5, 3, 1
Actual output: 1578032, 0, 3, 6, 6487408, 0
here is my code:
#include < stdio.h >
int main() {
input();
}
int input() {
int n;
printf("Enter The Number Of Elements You Want To Enter : ");
scanf("%d", & n);
int * ptr, i, ev = 0, od = 0;
ptr = (int * ) calloc(n, sizeof(int));
for (i = 0; i < n; i++) {
printf("Enter Number : ");
scanf("%d", (ptr + i));
if ( * (ptr + i) % 2 == 0) {
ev++;
} else {
od++;
}
}
sorteven( & ptr, ev, od, n);
}
int sorteven(int * ptr, int ev, int od, int n) {
int i, j = 0, swap = 0, * ptreven;
ptreven = (int * ) calloc(ev, sizeof(int));
for (i = 0; i < n; i++) {
if ( * (ptr + i) % 2 == 0) { *
(ptreven + j) = * (ptr + i);
j++;
}
}
for (i = 0; i < ev - 1; i++) {
for (j = 0; j < ev - i - 1; j++) {
if ( * (ptreven + j) > * (ptreven + j + 1)) {
swap = * (ptreven + j); *
(ptreven + j) = * (ptreven + j + 1); *
(ptreven + j + 1) = swap;
}
}
}
sortodd( & ptr, ev, od, n, & ptreven);
}
int sortodd(int * ptr, int ev, int od, int n, int ptreven) {
int i, k = 0, swap = 0, * ptrodd, j;
ptrodd = (int * ) calloc(od, sizeof(int));
for (i = 0; i < n; i++) {
if ( * (ptr + i) % 2 != 0) { *
(ptrodd + k) = * (ptr + i);
k++;
}
}
for (i = 0; i < od - 1; i++) {
for (j = 0; j < od - i - 1; j++) {
if ( * (ptrodd + j) < * (ptrodd + j + 1)) {
swap = * (ptrodd + j); *
(ptrodd + j) = * (ptrodd + j + 1); *
(ptrodd + j + 1) = swap;
}
}
}
merge( & ptr, ev, od, n, & ptreven, & ptrodd);
}
int merge(int * ptr, int ev, int od, int n, int * ptreven, int * ptrodd) {
int * ptrmerge, i, j;
ptrmerge = (int * ) calloc(n, sizeof(int));
for (i = 0; i < ev; i++) { *
(ptrmerge + i) = * (ptreven + i);
}
for (i = ev, j = 0; i < n; i++, j++) { *
(ptrmerge + i) = * (ptrodd + j);
}
display( & ptrmerge, n);
}
int display(int * ptrmerge, int n) {
int i;
printf("OUTPUT : ");
for (i = 0; i < n; i++) {
printf(" %d ", * (ptrmerge + i));
}
}

Answer 1

like this
#include <stdio.h>
#include <stdlib.h>
void input(void);
int main(void){
input();
}
void sorteven(int *ptr, int n);
void sortodd(int *ptr, int n);
void display(int *ptt, int n);
void input(void){
int n;
printf("Enter The Number Of Elements You Want To Enter : ");fflush(stdout);
scanf("%d", &n);
int *ptr, i, ev = 0, od = 0;
if((ptr = calloc(n, sizeof(int)))==NULL){
perror("malloc");
exit(EXIT_FAILURE);
}
for (i = 0; i < n; i++){
int v;
printf("Enter Number : ");fflush(stdout);
scanf("%d", &v);
if(v % 2 == 0){
ptr[ev++] = v;
} else {
ptr[n - ++od] = v;
}
}
sorteven(ptr, ev);
sortodd(ptr + ev, od);
display(ptr, n);
free(ptr);
}
void sorteven(int *ptr, int n){
//sort to ascending order
int i, j, temp;
for (i = 0; i < n - 1; i++){
for (j = 0; j < n - i - 1; j++){
if(ptr[j] > ptr[j + 1]){
int temp = ptr[j];
ptr[j] = ptr[j + 1];
ptr[j + 1] = temp;
}
}
}
}
void sortodd(int *ptr, int n){
//sort to descending order
int i, j, temp;
for (i = 0; i < n - 1; i++){
for (j = 0; j < n - i - 1; j++){
if(ptr[j] < ptr[j + 1]){
int temp = ptr[j];
ptr[j] = ptr[j + 1];
ptr[j + 1] = temp;
}
}
}
}
void display(int *ptr, int n){
int i;
printf("\nOUTPUT : ");
for (i = 0; i < n; i++){
if(i)
putchar(' ');
printf("%d", ptr[i]);
}
putchar('\n');
}