关于#链表#的问题，如何解决？

Question

1.链表创建成功之后卡了，
2.sclearnlink函数报错说t 是NULL，但是我的if里面不应该已经把l->next == nullptr的情况排除了吗
3.创建链表给他输入值的时候，怎么样写就是按空格分隔数据，怎么样写可以是实现一行一个数据（按行分隔数据）

#include <iostream>
using namespace std;
#define elementype int
#define Maxsize 20 
//链式栈
typedef struct sqlink {//链栈定义
    elementype data;
    sqlink* next;
}*linksq;


//获取栈的元素个数
int slength(const linksq& s) {
    return s->data;
}
//遍历栈元素输出
void sqnum(linksq& s) {
    int m = slength(s);
    cout << "从栈顶向下数据依次为" << endl;
    for (int i = 0; i < m; i++) {
        cout << s->next->data << " ";
    }

}

//链栈的初始化
bool initsqlink(linksq&l) {
    l = new sqlink;
    l->next = nullptr;
    l->data = 0; //将元素个数放在top上面指针的data 域里
    return true;
}
//判断栈是否为空
bool sisemptye(linksq&l) {
    if (l->next == nullptr) {
        return true;

    }
    else return false;

}


//压栈
void spush(linksq& s, const elementype& e) {
    sqlink* t = new sqlink;
    t->data = e;
    t->next = s->next;
    s->next = t;
}

//弹栈
void spop(linksq& s, elementype& e) {
    sqlink* p = s->next;
    e = p->data;
    s->next = p->next;
(s->data)--;
delete p;
}

//创建栈
bool creatsq(linksq& s) {
    cout << "请输入元素个数" << endl;
    cin >> s->data;
    elementype input;
    cout << "请输入栈的元素" << endl;
    for (int i = 0; i < s->data; i++) {
        cin >> input;
        spush(s, input);
        return true;
    }
    /* for (int i = 0; i < s->data; i++) {
         sqlink* p = new sqlink;
         cin >> p->data;
         p->next = s->next;
     }*/
}
//清空栈
bool sclearnlink(linksq& l) {
    if (l->next == nullptr) {
        cout << "链表为空" << endl;
        return false;
    }
    linksq t = l->next;
    linksq p = t;

    while (p) {
        p = t;
        t = t->next;
        delete p;
    }
    l->data = 0;
    l->next = nullptr;
    return 0;
}

//销毁栈
bool destorysq(linksq& l) {
    if (l == nullptr) {
        cout << "链表不存在" << endl;

    }
    linksq t = l->next, p;
    while (t) {
        p = t;
        t = t->next;
        delete p;
    }
    return true;
}

int main()
{
    //链栈
    linksq n = new sqlink;
    if (initsqlink(n))
    {
        cout << "链式栈初始化成功" << endl;
        if (creatsq(n)) {
            cout << "链表创建成功！" << endl;

        }
        else cout << "链表初始化失败！" << endl;

    }
    sqnum(n);
    elementype q;
    cout << "请输入要入栈的元素" << endl;
    cin >> q;
    spush(n, q);
    elementype f;
    spop(n, f);
    cout << "弹出元素为" << f<<endl;
    int w;
    cout << "清空栈则输入1，不清空则输入0" << endl;
    cin >> w;
    if (w) {
        if (sclearnlink(n))cout << "清空成功" << endl;
        else cout << "清空失败" << endl;

    }
    
}

Answer 1

initsqlink里不用再new链表了啊，main里已经new了
整体有不少错误，修改如下：

 
#include <iostream>
using namespace std;
#define elementype int
#define Maxsize 20 
//链式栈
typedef struct sqlink {//链栈定义
    elementype data;
    sqlink* next;
}*linksq;
 
 
//获取栈的元素个数
int slength(const linksq& s) {
    return s->data;
}
//遍历栈元素输出
void sqnum(linksq& s) {
    int m = slength(s);
    linksq p = s->next;
    cout << "从栈顶向下数据依次为" << endl;
    for (int i = 0; i < m; i++) {
        cout << p->data << " ";
        p = p->next;
    }
 
}
 
//链栈的初始化
bool initsqlink(linksq&l) {
    l->next = nullptr;
    l->data = 0; //将元素个数放在top上面指针的data 域里
    return true;
}
//判断栈是否为空
bool sisemptye(linksq&l) {
    if (l->next == nullptr) {
        return true;
 
    }
    return false;
 
}
 
 
//压栈
void spush(linksq& s, const elementype& e) {
    sqlink* t = new sqlink;
    t->data = e;
    t->next = s->next;
    s->next = t;
    s->data++;
}
 
//弹栈
void spop(linksq& s, elementype& e) {
    sqlink* p = s->next;
    if(p==NULL)
        return;
    e = p->data;
    s->next = p->next;
    (s->data)--;
    delete p;
}
 
//创建栈
bool creatsq(linksq& s) {
    cout << "请输入元素个数" << endl;
    int n;
    cin>>n;
    s->data = 0;
    elementype input;
    cout << "请输入栈的元素" << endl;
    for (int i = 0; i < n; i++) {
        cin >> input;
        spush(s, input);
    }
    return true; 
}
//清空栈
bool sclearnlink(linksq& l) {
    if (l->next == nullptr) {
        cout << "链表为空" << endl;
        return false;
    }
    linksq t = l->next;
    linksq p = t;
 
    while (t) {
        p = t;
        t = t->next;
        delete p;
    }
    l->data = 0;
    l->next = nullptr;
    return true;
}
 
//销毁栈
bool destorysq(linksq& l) {
    if (l == nullptr) {
        cout << "链表不存在" << endl;
 
    }
    linksq t = l->next, p;
    while (t) {
        p = t;
        t = t->next;
        delete p;
    }
    return true;
}
 
int main()
{
    //链栈
    linksq n = new sqlink;
    if (initsqlink(n))
    {
        cout << "链式栈初始化成功" << endl;
        if (creatsq(n)) {
            cout << "链表创建成功！" << endl;
 
        }
        else cout << "链表初始化失败！" << endl;
 
    }
    sqnum(n);
    elementype q;
    cout << "请输入要入栈的元素" << endl;
    cin >> q;
    spush(n, q);
    elementype f;
    spop(n, f);
    cout << "弹出元素为" << f<<endl;
    int w;
    cout << "清空栈则输入1，不清空则输入0" << endl;
    cin >> w;
    if (w) {
        if (sclearnlink(n))cout << "清空成功" << endl;
        else cout << "清空失败" << endl;
 
    }
    system("pause");
}