为什么我的 while 循环条件不起作用？

Question

This program asks for number irrespective of what character you enter. Then the problem is in the while loop.

Why my while loop condition not working ? checking temp isn't equal to NULL

#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>

typedef struct node
{
    int num;
    struct node *ptr;
} nod;
nod *head = NULL;

void insert()
{
    int n;
    nod *temp = (struct node*) malloc(sizeof(struct node));
    printf("Enter nnumber \n");
    scanf("%d", &n);
    temp->num = n;
    temp->ptr = NULL;
    if (head == NULL)
    {
        head = temp;
    }
    else
    {
        temp->ptr = head;
        head = temp;
    }
}

void display()
{
    nod* temp;
    temp = head;
    while (temp != NULL)
    {
        printf(" --> %d", temp->num);
        temp = temp->ptr;
    }
}

int main()
{
    char ch;
    do
    {
        insert();
        display();
        char ch;
        printf("\n enter more data ? (y/n)");
        scanf("\n %c", &ch);
    }
    while (ch != 'n');
    return 0;
}

Thanks in advance

Answer 1

Why you are re-declare char ch inside the loop ?

Remove char ch inside loop and fix your problem. Like,

int main()
{
    char ch;
    do
    {
        insert();
        display();
        printf("enter more data ? (y/n)\n");
        scanf(" %c", &ch);
    }
    while (ch != 'n');    
    return 0;
}