注册 登录
编程论坛 → C++教室

关于连续释放链表空间的问题，求指导！

泡vs泡happy 发布于 2013-12-21 21:49， 322 次点击
是一元多项式运算的程序，在建立了各个链表之后，在最后想撤销它们，可是连续调用六遍会出错，但是调用两遍却没事，不知是链表的问题还是del（）函数的问题，下面是我的程序，希望大侠能给出指导！（问题出在main（）最后的del（）上  ）
程序代码：
#include<iostream>
#include<cmath>
using namespace std;
typedef struct node{
   float a;
   int b;
   struct node *next;

}lnode,*linklist;



linklist creat_linklist(int k){
  linklist H;
  lnode *p,*r;
  int max,mid;
  float mark;
  H=r=NULL;

 for(int i=0;i<k;i++){
     cout<<"请输入第"<<i+1<<"项的<系,指>：";
     cin>>mark>>mid;
     while(mark==0){
     cout<<"系数不能为零，请重新输入<系，指>：";
     cin>>mark>>mid;
     }
     if(i==0){
         max=mid;
     }
     else{
     while(mid<=max){
         cout<<endl;
     cout<<"请按照指数依次升高的原则重新输入<系，指>：";
     cin>>mark>>mid;
     
     }
    }
     
    max=mid;
   
    p=new lnode;
    if(!p){cout<<"分配空间错误！"<<endl; exit(1);}
    p->a=mark;
    p->b=max;
   
   
   

    cout<<endl;
    if(H==NULL)
        H=p;
    else
        r->next=p;
        r=p;
    }

 r->next=NULL;//若链表末尾不设置为空，其他函数将无法正常终止循环，因为s1=s1->next无法正常结尾；
 cout<<endl;

return H;

}






void output(linklist H){
   
lnode *s=NULL;
s=H;

while(s){

    if(s!=H&&s->a>0){
        
         if(s->b==1&&s->a==1)
            cout<<"+x";
        
         else if(s->b==1){

             cout<<"+"<<s->a<<"x";
         }
         else if(s->b==0)
             cout<<"+"<<s->a;
        else if(s->a==1)
            
            cout<<"+"<<"x^"<<s->b;
        
        else
            cout<<"+"<<s->a<<"x^"<<s->b;
    }
    else{
        if(s==H&&s->a==0&&s->next==NULL)
            cout<<"0";
        else if(s->a==0){
            s=s->next;
            continue;
        }
        
        else if(s->b==0){
         
            cout<<s->a;
        }
        else if(s->b==1&&s->a==1)
            
            cout<<"x";
            
        else if(s->b==1&&s->a==-1)
            cout<<"-x";
        else if(s->b==1)
            cout<<s->a<<"x";
        else if(s->a==-1)
            cout<<"-x^"<<s->b;
        else if(s->a==1)
            cout<<"x^"<<s->b;
        else
            cout<<s->a<<"x^"<<s->b;
    }        
            
            
            s=s->next;
   
            

 }

}

linklist add(linklist H1,linklist H2){

 linklist H3=NULL;

 lnode *s1,*s2,*r;

 lnode *pre;

 int k=-1;

 s1=H1;

 s2=H2;

 r=H3=NULL;

 while(s1!=NULL&&s2!=NULL){

 if(s1->b==s2->b){
     if(s1->a+s2->a==0){
         if(s1->next==NULL&&s2->next==NULL){
             k=0;
            
             s1=s1->next;
             s2=s2->next;
         }
         else if(s1->next==NULL&&s2->next!=NULL){
             s1=s1->next;
             s2=s2->next;
             k=1;
            
        //     continue;
         }
         else if(s2->next==NULL&&s1!=NULL){
             s1=s1->next;
             s2=s2->next;
             k=2;
        //     continue;
         }
         else{
         s1=s1->next;
         s2=s2->next;
    //     continue;
         }
     
     }


     else{
     pre=new lnode;
     
     pre->a=s1->a+s2->a;
     
     pre->b=s1->b;
     



     if(H3==NULL)
         H3=pre;
                  
     else
     r->next=pre;
     r=pre;
     r->next=NULL;//此处同上处一样，若不将新建链表末尾置为NULL关于其循环将无法正常终止！！！
     s1=s1->next;
     s2=s2->next;
     }     
     
   

 }

 else if(s1->b<s2->b){
     pre=new lnode;
     pre->a=s1->a;
     pre->b=s1->b;
      if(H3==NULL)
         H3=pre;
         
         
     else
     r->next=pre;
     r=pre;
     s1=s1->next;
   
     

 }

 else

 {
     pre=new lnode;
     pre->a=s2->a;
     pre->b=s2->b;
      if(H3==NULL)
         H3=pre;
         
         
     else
     r->next=pre;
     r=pre;
     
     s2=s2->next;

  }



 }



 if(k==0){
     if(H3==NULL){
     H3=new lnode;
     H3->a=0;
     H3->b=0;
     H3->next=NULL;
     }
     r->next=NULL;


 }

 else if(k==1&&s2!=NULL){
     pre=new lnode;
     pre->a=s2->a;
     pre->b=s2->b;
      if(H3==NULL)
         H3=pre;
         
         
     else
     r->next=pre;
     r=pre;
     r->next=NULL;

 

 

 }
   
else if(k==2&&s1!=NULL){
    pre=new lnode;
     pre->a=s1->a;
     pre->b=s1->b;
      if(H3==NULL)
         H3=pre;
         
         
     else
     r->next=pre;
     r=pre;
     r->next=NULL;

}
   

 
else if(s1!=NULL)
     r->next=s1;
else
     r->next=s2;
     


 return H3;
}
  









linklist sub(linklist H1,linklist H2){

 linklist H4=NULL;

 lnode *s1,*s2,*r;

 lnode *pre;

 int k=-1;

 s1=H1;

 s2=H2;

 r=H4=NULL;

 while(s1!=NULL&&s2!=NULL){

 if(s1->b==s2->b){
     if(s1->a-s2->a==0){
         if(s1->next==NULL&&s2->next==NULL){
             k=0;
            
             s1=s1->next;
             s2=s2->next;
         }
         else if(s1->next==NULL&&s2->next!=NULL){
             s1=s1->next;
             s2=s2->next;
             k=1;
            
        //     continue;
         }
         else if(s2->next==NULL&&s1->next!=NULL){
             s1=s1->next;
             s2=s2->next;
             k=2;
        //     continue;
         }
         else{
         s1=s1->next;
         s2=s2->next;
    //     continue;
         }
     
     }


     else{
     pre=new lnode;
     
     pre->a=s1->a-s2->a;
     
     pre->b=s1->b;
     



     if(H4==NULL)
         H4=pre;
                  
     else
     r->next=pre;
     r=pre;
     r->next=NULL;//此处同上处一样，若不将新建链表末尾置为NULL关于其循环将无法正常终止！！！
     s1=s1->next;
     s2=s2->next;
     }     
     
   

 }

 else if(s1->b<s2->b){
     pre=new lnode;
     pre->a=s1->a;
     pre->b=s1->b;
      if(H4==NULL)
         H4=pre;
         
         
     else
     r->next=pre;
     r=pre;
     s1=s1->next;
   
     

 }

 else

 {
     pre=new lnode;
     pre->a=-s2->a;
     pre->b=s2->b;
      if(H4==NULL)
         H4=pre;
         
         
     else
     r->next=pre;
     r=pre;
     
     s2=s2->next;

  }



 }



 if(k==0){
     if(H4==NULL){
     H4=new lnode;
     H4->a=0;
     H4->b=0;
     H4->next=NULL;
     }
    else
     r->next=NULL;


 }

 else if(k==1&&s2!=NULL){
     while(s2!=NULL){
     pre=new lnode;
     pre->a=-s2->a;
     pre->b=s2->b;
      if(H4==NULL)
         H4=pre;
         
         
     else
     r->next=pre;
     r=pre;
     r->next=NULL;
     s2=s2->next;
     }

 

 

 }
   
else if(k==2&&s1!=NULL){
    pre=new lnode;
     pre->a=s1->a;
     pre->b=s1->b;
      if(H4==NULL)
         H4=pre;
         
         
     else
     r->next=pre;
     r=pre;
     r->next=NULL;

}
   

 
else if(s1!=NULL){
    r->next=s1;
    while(s1!=NULL){
        
        s1->a=s1->a;
        s1=s1->next;
    }
}
else{
    r->next=s2;
    while(s2!=NULL){
        s2->a=-s2->a;
        s2=s2->next;
    }
   
}
     


 return H4;


}







linklist der(linklist H){
   
lnode *p,*s;
p=H;
while(p){
    if(p->b==0){
        if(p==H){
            s=p;
            p=p->next;
            H=p;
            delete s;
        }
        else{   
            p->a=0;
            p=p->next;
        }

    }
    else{
    p->a=p->a*p->b;
   
    p->b=p->b-1;
p=p->next;
    }
   
   
}
return H;


}



   
void del(linklist H){
lnode *p,*s;
p=H;
while(p){
    s=p;
    p=p->next;
    delete s;
  }

}   







int main(){
linklist H1=NULL,H2=NULL,H3=NULL,H4=NULL,H5=NULL,H6=NULL;
int m,n;


 cout<<"                温馨提示：多项式请按指数依次递增的规则输入"<<endl;   

 cout<<"请输入多项式a的项数";

 cin>>m;

 while(m<=0){
     cout<<endl;
     cout<<"不符合数学逻辑，请重新输入:";
     cin>>m;
     

 }


 H1=creat_linklist(m);

 

 cout<<"请输入多项式b的项数";

 cin>>n;
  while(n<=0){
     cout<<endl;
     cout<<"不符合数学逻辑，请重新输入:";
     cin>>n;
  }
     
  H2=creat_linklist(n);
  
  cout<<"多项式a为:";
  output(H1);
  cout<<endl;


 

 cout<<"多项式b为:";

 output(H2);

 cout<<endl;

 H3=add(H1,H2);

 cout<<"相加的结果为：";

 output(H3);

 cout<<endl;

 

 cout<<"相减的结果为：";

 H4=sub(H1,H2);

 output(H4);

 cout<<endl;


 cout<<"对a的求导结果：";

 H5=der(H1);

 output(H5);

 cout<<endl;

 

 cout<<"对b的求导结果：";

 H6=der(H2);

 output(H6);


 cout<<endl;


 del(H1);

 del(H2);

 del(H3);

 del(H4);

 del(H5);

 del(H6);

 cout<<"各链表空间释放完毕！！！"<<endl;

 return 0;
}


[ 本帖最后由 泡vs泡happy 于 2013-12-21 22:24 编辑 ]
1 回复
#2
蚕头燕尾2013-12-25 19:09
在CSDN得到了答案的话别忘了到这里贴出来，大家都好学习学习。
1
©2025, BC-CN.NET
电脑版