Please help : Data structure problem (recieve only integer data and print 5 data in each line)

Display Data :
1 6 16 8 30
9 65 25 7 9
15 36 95 4 2
    .
    .
    .

#include <stdio.h>
#include <stdlib.h>
#define FUNC_SIZE 4  // size of pointer function array

// structure declare

typedef struct node_record {
 int nData;
 struct node_record *next;
} _node;

typedef _node* list_node;  // structure pointer's data type declare
list_node head = NULL;  // structure pointer variable declare
int list_menu(int*);    // menu function
int input_num(int*, int);   // input function
int insert_node(void);   // input in node function
int delete_node(void);   // delete node's content function
int print_node(void);   // print function
int end_proc(void);    // quit function

// main function
int main(void)
{
	int nSelect=0, nRetry=1;  // select menu,  repeat variable
	int (*func_node[FUNC_SIZE])(void)={insert_node, delete_node, print_node, end_proc};  // pointer function array declare and initialize to functions
	while(nRetry)  // repeat
	{
		list_menu(&nSelect);  // call main function
		nRetry = func_node[nSelect-1]();   //call correspond function
	}
	return 0;
}

// menu function
int list_menu(int* pSelect)
{
	puts("********MENU********");
	puts("* 1. Insert        *");
	puts("* 2. Remove        *");
	puts("* 3. Print         *");
	puts("* 4. End           *");
	puts("********************");
	do 
	{
		fflush(stdin);
		printf("*Choice : ");
		scanf_s("%d", pSelect);   // input
	} while(*pSelect > 4 || *pSelect < 1);   // choose range
	return 0;
}

//  input function
int input_node(int* pNum, int nFlag)
{
	printf("*%s : ", (nFlag == 1)?"Input Value":"Want to delete Value");
	scanf_s("%d", pNum);  // input
	return 0;
}

// input function of list
int insert_node(void)
{
	list_node temp, ptr, preptr;  // structure pointer variable declare
	int nData=0;   // variable for input
	preptr = head;  // structure pointer variable "head" is stored in "preptr"
	temp = (list_node)malloc(sizeof(_node));   // allocate memory in variable "temp"
	input_node(&nData, 1); 
	if(temp == NULL)  // if memory doesn't be allocate very well
	{
		printf("*Memory wasn't enough.");
		exit(1);   // quit  unusually
	}
	temp->nData = nData;  // store input data in "temp"'s parameter "nData"
	if(head == NULL || head->nData > nData)  // the case "head" is "NULL" OR the case "head"'s parameter nData is larger than input value
	{
		temp->next = head;  // "head"'s address(at this time) is stored in "next" parameter of "temp" structure pointer
		head = temp;    // "temp" is stored in "head" so "head" is changed
	}
	else  // exception
	{
		ptr = preptr->next;  // address value that "next" of "preptr(head)" has is copied in "ptr"
		while(ptr != NULL)  // the case that "ptr" isn't NULL
		{
			if.(ptr->nData > nData)  //compare with "nData"value of "ptr" and Input value - the case that ptr->nData is larger than Input value
				break;   // quit repeat sentence
			preptr = ptr;   // copy "ptr"(in this time) to "preptr" (increase  one by one)
			ptr = ptr->next;  // "ptr->next"(in this time) copy address value to "ptr"(increase  one by one)
		}
		temp->next = ptr;   // store address of "ptr"(in this time) in "temp->next"(temp --> ptr)
		preptr->next = temp;  // store address of "temp" in "preptr->next"(preptr --> temp)
	}
	return 1;
}


// delete function of list
int delete_node(void)
{
	list_node preptr, ptr;  // structure pointer variable declare
	int nData=0;     // data to delete
	input_node(&nData, 2); // input to delete value
	if(head == NULL)   // if "head" is "NULL", there are no data
	{
		puts("*Data does not exist.");
	}
	else if(head->nData == nData)  // if "head->nData" is same with data that want to delete 
	{
		preptr = head;    // store address of "head" in "preptr"
		head = preptr->next;  // address value of "preptr(head)->next" is replaced to "head"("head" is change to address value that "head" points)
		free(preptr);     // clear "preptr" memory
		puts("*Data was erased.");  // print message
		return 1;
	}
	else
	{
		preptr = head;    // store address of "head" in "preptr"
		ptr = preptr->next;   // store next address that "preptr(head)" (that stored above is point) in "ptr"
		while(ptr != NULL && ptr->nData != nData)  
			preptr = ptr;    
			ptr = ptr->next;   
		}
		
		if(ptr == NULL)  
			puts("*Corresponding data does not exist."); 
		else 
		{
			preptr->next = ptr->next;  // give address of "ptr->next" to "preptr->next" so "pretr" points next address that "ptr" is pointing
			free(ptr);       // clear memory about "ptr"
			puts("*Data was erased.");  // print message
		}
	}
	return 1;
}

// list print function
int print_node(void)
{
	int nIdx=1;   // print counter
	list_node preptr;  // structure pointer variable
	preptr = head;  // copy "head" to "preptr"
 
	if(preptr == NULL)  // there is no data when "preptr(head)" is "NULL"
		puts("*Data does not exist.");
	else  // case that isn't "NULL"
	{
		printf("*Display Data : ");
		while(preptr != NULL)  // repeat when "preptr" isn't "NULL"
		{
			printf("%d ",  preptr->nData); //print data
			preptr = preptr->next;  // substitute "preptr->next"'s address value(in this time) to "preptr"
		}
		printf("\n");
	}
	return 1;
}

// quit function
int end_proc(void)
{
	list_node temp;  // structure pointer variable
 
	while(head != NULL)   // case that "preptr(head)" isn't "NULL"
	{
		temp = head;    // copy "head" to "preptr"
		head = temp->next;  // copy "temp(head)->next"'s address to "head"
		free(temp);     // clear "temp" variable memory of this time
	}
	puts("Quit the program.");    // print quit message
	return 0;
}