切换案例错误重新声明＆＃39; manu＆＃39;

Question

切换错误重新声明＆＃39; manu＆＃39;如何解决这个问题？

#include<stdio.h>
#include<conio.h>
struct node
{
    int data;
    struct node *nxtadd;
}*head=NULL,*temp,*temp1;
void insert_first()
{
    if(head==NULL)
    {
        head=(struct node *)malloc(sizeof(struct node));
        scanf("%d",&head->data);
        head->nxtadd=NULL;
    }
    else
    {
        temp1=head;
        while(temp1->nxtadd!=NULL)
        {
            temp=temp1->nxtadd;
        }
    }
}
void display()
{
        if(head==NULL)
        {
            printf("No LINK LIST Crated , First Insert Record.");
        }
        else
        {
            temp1=head;
            while(temp1!=NULL)
            {
                printf("%d",&head->data);
                temp=temp1->nxtadd;
            }
        }
}
void delete_first()
{
    if(head==NULL)
    {
        printf("No LINK-LIST Created, First insert record(s).");
    }
    else
    {
        temp=head;
        head=head->nxtadd;
        free(temp);
        display();
    }
}
void sub_manu_insert()
{
    int a;
    while(1)
    {
        printf("------------------------------------------------------------/n");
        printf("                           LINK LIST - Sub Manu.                         \n");
        printf("------------------------------------------------------------/n");
        printf("select Opration\n");
        printf("------------------------------------------------------------/n");
        printf("1). insert-first\n");
        printf("2). insert-last\n");
        printf("3). Exit\n");
        printf("------------------------------------------------------------/n");
        scanf("%d",&a);
        switch(a)
        {
            case 1:
                insert_first();
                break;
            case 2:
                insert_last();
                break;
            case 3:
                clrscr();
                manu();
                break;
               default:
                printf("Enter Proper Number..");
        }
    }
}
void sub_manu_delete()
{
    int a;
    while(1)
    {
        printf("------------------------------------------------------------/n");
        printf("                           LINK LIST - Sub Manu.                         \n");
        printf("------------------------------------------------------------/n");
        printf("select Opration\n");
        printf("------------------------------------------------------------/n");
        printf("1). Delete-first\n");
        printf("2). Delete-last\n");
        printf("3). Exit\n");
        printf("------------------------------------------------------------/n");
        scanf("%d",&a);
        switch(a)
        {
            case 1:
                delete_first();
                break;
            case 2:
                delete_last();
                break;
            case 3:
                clrscr();
                manu();
                break;
            default:
                printf("Enter Proper Number..");
        }
    }

}
void manu()
{
    int a;
    while(1)
    {
        printf("------------------------------------------------------------/n");
        printf("                           LINK LIST                         \n");
        printf("------------------------------------------------------------/n");
        printf("select Opration\n");
        printf("------------------------------------------------------------/n");
        printf("1). Insert New Record\n");
        printf("2). Display Record\n");
        printf("3). Delete Record\n");
        printf("4). Exit\n");
        printf("------------------------------------------------------------/n");
        scanf("%d",&a);
        switch(a)
        {
            case 1:
                sub_manu_insert();
                break;
            case 2:
                display();
                break;
            case 3:
                sub_manu_delete();
                break;
            case 4:
                sub_manu_update();
                break;
            case 5:
                exit(0);
                break;
            default:
                printf("Enter Proper Number...\n");
                break;
        }
    }
}
void main()
{
    clrscr();
    manu();
    getch();
}

Answer 1

在C中，应该在使用函数之前声明或定义函数。否则，将为该函数创建一个默认声明，如果这与真实定义不匹配，您将收到错误。

所以在程序开头放一个函数声明：

void manu();