#include<iostream>
using namespace std;
#include<math.h>
#include<stdlib.h>
#define maxsize 20
int n;
typedef struct node
{ int *data;
int length;
int listsize;
}sqlist;
void createsqlist(sqlist &L)
{ L.data=(int*)malloc(sizeof(int)*maxsize);
if(!L.data)
exit(1);
}
void initsqlist(sqlist &L)
{int i;
int *p;
p=L.data;
cout<<"enter your list's number:"<<"\t";
cin>>n;
cout<<"enter your list's elements:"<<"\t";
for(i=0;i<n;i++,p++)
cin>>*p;
}
void outputsqlist(sqlist &L)
{int *q;
q=L.data;
    cout<<"your sqlist is:"<<endl;
for(int i=0;i<n;i++,q++)
cout<<*q<<"\t";
}
void insertsqlist(sqlist &L)
{int c,j;
cout<<"enter you want insert data:"<<"\t";
cin>>c;
if(c<=L.data[0])
j=0;
else
if(c>=L.data[n-1])
j=n;
else
for(int i=0;c>L.data[i];i++)
j=i;
for(;j<n;n--)
L.data[n]=L.data[n-1];
L.data[j]=c;
cout<<L.data[1];
cout<<endl;
n=n+1;
cout<<"inserted list is :"<<endl;
for(int h=0;h<n;h++)
cout<<L.data[h]<<"\t";
cout<<endl;
}
int main()
{sqlist L1;
createsqlist(L1);
initsqlist(L1);
outputsqlist(L1);
insertsqlist(L1);
return 0;
}

我把你这个格式稍微缩进了下，否则代码可读性不高，解决如下：
 

#include<iostream>
using namespace std;
#include<math.h>
#include<stdlib.h>
#define maxsize 20

int n;
typedef struct node
{ 
    int *data;
    int length;
    int listsize;
}sqlist;

void createsqlist(sqlist &L)
{ 
    L.data=(int*)malloc(sizeof(int)*maxsize);
    if(!L.data)
        exit(1);
}

void initsqlist(sqlist &L)
{
    int i;
    int *p;
    p=L.data;
    cout<<"enter your list's number:"<<"\t";
    cin>>n;
    L.length = n;
    cout<<"enter your list's elements:"<<"\t";
    for(i=0;i<n;i++,p++)
    {
        cin>>*p;
    }
}

void outputsqlist(sqlist &L)
{
    int *q;
    q=L.data;
    cout<<"your sqlist is:"<<endl;
    for(int i=0;i<n;i++,q++)
    {
        cout<<*q<<"\t";
    }
}

void insertsqlist(sqlist &L)
{
    int c,j = 0;
     cout<<"enter you want insert data:"<<"\t";
    cin>>c;
    /* 确定插入位置 */
    if(c<=L.data[0])
    {
        j=0;
    }
    else if(c>=L.data[n-1])
    {
        j=n; 
    }    
    else
    {
#if 0  
        for(int i=0;c>L.data[i]||i<n;i++)  /* 在第一个和最后一个之间依次比较 */
        {
            if(c <= L.data[i])
            {
                j=i;
                break;
            }
        }
#else  /* 这个地方我有点画蛇添足了，后来改正的 */
       int i=0;
       for(;c>L.data[i];i++);
       j=i;
#endif
    }

    /* 下面开始插入操作 */
    n = L.length;

    for(;j<n;n--)
    {
        L.data[n]=L.data[n-1];
    }
    L.data[j]=c;

    L.length += 1; // 因为插入一个，所以长度加1
    n = L.length;

    cout<<"inserted list is :"<<endl;

    for(int h=0;h<n;h++)
    {
        cout<<L.data[h]<<"\t";
    }    
    cout<<endl;    
}
int main()
{
    sqlist L1;
    createsqlist(L1);
    initsqlist(L1);
    outputsqlist(L1);
    insertsqlist(L1);
    return 0;
}

[此贴子已经被作者于2015-11-11 09:00编辑过]

大致实现你要的功能，哪块要是不清晰咱再讨论讨论

#include<stdio.h>
#include<iostream.h>
#include <stdlib.h>
#define maxsize 20
int n;
typedef struct
{int * data;
int length;
int listsize;
}sqlist;
void creatsqlist(sqlist &list)
{list.data=(int*)malloc(sizeof(int)*maxsize);
if(!list.data)
exit(1);
list.length=0;
list.listsize=maxsize;
}
void initsqlist(sqlist &list)
{int i;
  int * p;
cout<<"plese enta you wish number"<<endl;
cin>>n;
p=list.data;
cout<<"please enta your data in order"<<endl;
for(i=0;i<n;i++,p++)
{cin>>*p;
list.length++;}
cout<<"your list is"<<endl;
for(i=0;i<n;i++)
cout<<list.data[i]<<"\t";
cout<<endl;
}
void insert(sqlist &list)
{
    int a,b;
int k=0;

cout<<"please enter the insertdata's number"<<endl;
cin>>b;
if(b>list.data[list.length-1])
a=list.length+1;
else
{while(b>list.data[k])
k=k+1;
a=k+1;}
cout<<a<<endl;
{int j;
for(j=list.length;j>=a;j--)
list.data[j]=list.data[j-1];
list.data[a-1]=b;
list.length++;
}
cout<<"the newinsert list is"<<endl;
for(int i=0;i<=n;i++)
cout<<list.data[i]<<"\t";
cout<<endl;
}
int main()
{sqlist list1;
creatsqlist(list1);
initsqlist(list1);
insert(list1);

return 0;
}