想请教一下在函数sqlist MergeList中，如果有重复的部分，最后运行出来结尾会有一个零（重复的数据只保留一个，但是该数据占用的内存没有释放），如何改进？

Question

#define overflow -1
#define ok 1
#define error 0
#define maxsize 16
#define increment 10
#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
typedef int status;
typedef int elemtype;
typedef struct
{
    elemtype *elem;
    int length;
    int listsize;
} sqlist;

//初始化 
status initlist(sqlist &L)
{
    L.elem = (elemtype *)malloc(maxsize * sizeof(elemtype));
    if (!L.elem)
        exit(overflow);  
    L.length = 0;
    L.listsize = maxsize;
    return ok;
}

//创建
sqlist creata_list(sqlist L)
{
    int i=0,N;
    printf("input length you want -->\n");
    scanf("%d",&N);
    while( i!= N )
    {
        scanf("%d",&L.elem[i]);
        i++;
    }
    L.length += N;
    return L;
}

//在指定位置插入数字 
status insertlist(sqlist &L, int i, elemtype e)
{
    if (i < 1 || i > L.length)
        return error;
    elemtype *p;
    int j;
    if (L.length >= L.listsize)
    {
        p = (elemtype *)realloc(L.elem, (L.listsize + increment) * sizeof(elemtype));
        if (!p)
            exit(overflow);
        L.elem = p;
        L.listsize += increment;
    }
    for (j = L.length - 1; j >= i - 1; --j)
        L.elem[j + 1] = L.elem[j];
    L.elem[j + 1] = e;
    L.length++;
    return ok;
}

//输出顺序表 
void printlist(sqlist L)
{
    int i;
    for (i = 0; i < L.length; i++)
        printf("%d ", L.elem[i]);
    printf("\n");
}

//删除相应位置数据 
status dellist(sqlist &L, int i, elemtype &e)
{
    int j;
    if (i < 1 || i > L.length)
        return error;
    e = L.elem[i - 1];
    for (j = i; j < L.length; j++)
        L.elem[j - 1] = L.elem[j];
    --L.length;
    return ok;
}

//获取相应位置数据 
int LocatedList(sqlist &L,int j)
{
     
    if(j<1 || j>L.length){
        printf("The specified location does not exist!");
        return error;
    }

    return L.elem[j-1] ;   //直接返回 
 }
 
//获取相关值的位置
int GetList(sqlist L,elemtype temp)
{
    int j;
    for( j=0 ; j<L.length ; j++){
    if(L.elem[j]==temp)  {
    return j;
    break;
}
}
    printf("dont exist!\n");
    return error;
 } 
 
//合并集合 
sqlist MergeList(sqlist La,sqlist Lb,sqlist *Lc) 
{
    Lc->length=La.length+Lb.length;
    Lc->listsize=Lc->length;
    
    elemtype *pa=La.elem,*pb=Lb.elem,*pc;
    pc=(elemtype*)malloc(Lc->length*sizeof(elemtype));            //申请新的内存
    Lc->elem=pc; 
    elemtype *pa_last,*pb_last;                                            //定义指向初地址和末地址的指针
    
    pa_last=La.elem+La.length-1;
    pb_last=Lb.elem+Lb.length-1;
    
    while((pa <= pa_last)&&(pb<=pb_last)){
        if(*pa < *pb) *pc++ = *pa++;
        else if(*pa > *pb) *pc++ = *pb++;
        else if(*pa = *pb) { *pc++ = *pa++; *pb++; };                //顺序存储，重复只存pa，pa，pb都后退 
    }
    
    while(pa <= pa_last) *pc++ = *pa++;
    while(pb <= pb_last) *pc++ = *pb++;                            //判空，不为空继续赋值，直到指向最后指针。
    return *Lc; 
}

//合并顺序表
sqlist CombineList(sqlist L1,sqlist L2,sqlist *L3)
{
    L3->length=L1.length+L2.length;
    L3->listsize=L3->length;
    
    elemtype *p1=L1.elem,*p2=L2.elem,*p3;
    p3=(elemtype*)malloc(L3->length*sizeof(elemtype));            //申请新的内存
    L3->elem=p3; 
    elemtype *p1_last,*p2_last;                                            //定义指向初地址和末地址的指针
    
    p1_last=L1.elem+L1.length-1;
    p2_last=L2.elem+L2.length-1;
    
    while (p1 <= p1_last && p2 <= p2_last) {
        if( *p1<=*p2 ) *p3++ = *p1++;
        else *p3++ = *p2++;
    }
    while(p1 <= p1_last) *p3++ = *p1++;
    while(p2 <= p2_last) *p3++ = *p2++;                            //判空，不为空继续赋值，直到指向最后指针。
    return *L3;
 } 

int main()
{
    sqlist LL;
    elemtype x,data;
    int r, i,j;
    if (!initlist(LL)) //初始化
        return error;

    printf("input data-->\n");       //创建 
    LL=creata_list(LL);
    
    
    printf("check Order table-->\n");       //显示 
    printlist(LL); 
    
    printf("value index-->\n");  //插入
    scanf("%d %d", &x, &r);
    insertlist(LL, r, x);
    printlist(LL);
    
    printf("index-->\n");  //删除
    scanf("%d", &r);
    dellist(LL,r,x);
    printlist(LL); 
    
    printf("input locate-->\n");
    scanf("%d",&j);
    data=LocatedList(LL,j);
    printf("the elem[%d] = %d\n",j,data);
    
    printf("input value-->\n");
    elemtype temp,place;
    scanf("%d",&temp);
    place=GetList(LL, temp);
    printf("%d = the elem[%d]\n",temp,place+1);
    
    sqlist La,Lb,Lc;                    //合并集合 
    printf("Create list La-->\n");
    initlist(La);
    La=creata_list(La);
    printf("check La\n");
    printlist(La);
    printf("Create list Lb-->\n");
    initlist(Lb);
    Lb=creata_list(Lb);
    printf("check Lb\n");
    printlist(Lb);
    printf("combine list-->\n");
    MergeList(La,Lb,&Lc);
    printlist(Lc);
    
    sqlist L1,L2,L3;                    //合并有序表 
    printf("Create list L1-->\n");
    initlist(L1);
    L1=creata_list(L1);
    printf("check L1\n");
    printlist(L1);
    printf("Create list L2-->\n");
    initlist(L2);
    L2=creata_list(L2);
    printf("check L2\n");
    printlist(L2);
    printf("combine list-->\n");
    MergeList(L1,L2,&L3);
    printlist(L3);
    
}

Answer 1

原代码第132行，if()里少了一个 ‘= ’号，其他处修改如下，供参考：

#define overflow -1
#define ok 1
#define error 0
#define maxsize 16
#define increment 10
#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
typedef int status;
typedef int elemtype;
typedef struct
{
    elemtype *elem;
    int length;
    int listsize;
} sqlist;
//初始化
status initlist(sqlist &L)
{
    L.elem = (elemtype *)malloc(maxsize * sizeof(elemtype));
    if (!L.elem)
        exit(overflow);
    L.length = 0;
    L.listsize = maxsize;
    return ok;
}
//创建
sqlist creata_list(sqlist L)
{
    int i=0,N;
    printf("input length you want -->\n");
    scanf("%d",&N);
    while( i!= N )
    {
        scanf("%d",&L.elem[i]);
        i++;
    }
    L.length += N;
    return L;
}
//在指定位置插入数字 
status insertlist(sqlist &L, int i, elemtype e)
{
    if (i < 1 || i > L.length)
        return error;
    elemtype *p;
    int j;
    if (L.length >= L.listsize)
    {
        p = (elemtype *)realloc(L.elem, (L.listsize + increment) * sizeof(elemtype));
        if (!p)
            exit(overflow);
        L.elem = p;
        L.listsize += increment;
    }
    for (j = L.length - 1; j >= i - 1; --j)
        L.elem[j + 1] = L.elem[j];
    L.elem[j + 1] = e;
    L.length++;
    return ok;
}
//输出顺序表 
void printlist(sqlist L)
{
    int i;
    for (i = 0; i < L.length; i++)
        printf("%d ", L.elem[i]);
    printf("\n");
}
//删除相应位置数据 
status dellist(sqlist &L, int i, elemtype &e)
{
    int j;
    if (i < 1 || i > L.length)
        return error;
    e = L.elem[i - 1];
    for (j = i; j < L.length; j++)
        L.elem[j - 1] = L.elem[j];
    --L.length;
    return ok;
}
//获取相应位置数据 
int LocatedList(sqlist &L,int j)
{
    if(j<1 || j>L.length){
        printf("The specified location does not exist!");
        return error;
    }
    return L.elem[j-1] ;   //直接返回 
 }
//获取相关值的位置
int GetList(sqlist L,elemtype temp)
{
    int j;
    for( j=0 ; j<L.length ; j++){
    if(L.elem[j]==temp)  {
    return j;
    break;
}
}
    printf("dont exist!\n");
    return error;
 } 
//合并集合 
sqlist MergeList(sqlist La,sqlist Lb,sqlist *Lc)
{
    int cnt=0;  //修改
    Lc->length=La.length+Lb.length;
    //Lc->listsize=Lc->length;  //修改
    elemtype *pa=La.elem,*pb=Lb.elem,*pc;
    pc=(elemtype*)malloc(Lc->length*sizeof(elemtype)); //申请新的内存
    Lc->elem=pc;
    elemtype *pa_last,*pb_last;     //定义指向初地址和末地址的指针
    pa_last=La.elem+La.length-1;
    pb_last=Lb.elem+Lb.length-1;
    while((pa <= pa_last)&&(pb<=pb_last)){
        if(*pa < *pb) *pc++ = *pa++;
        else if(*pa > *pb) *pc++ = *pb++;
        else if(*pa == *pb) { *pc++ = *pa++; *pb++;cnt++;}//顺序存储，重复只存pa，pa，pb都后退
    }            //修改 =
    while(pa <= pa_last) *pc++ = *pa++;
    while(pb <= pb_last) *pc++ = *pb++; //判空，不为空继续赋值，直到指向最后指针。
    while(cnt--) Lc->length--;  //修改
    Lc->listsize=Lc->length;
    return *Lc;
}
//合并顺序表
sqlist CombineList(sqlist L1,sqlist L2,sqlist *L3)
{
    L3->length=L1.length+L2.length;
    L3->listsize=L3->length;
    elemtype *p1=L1.elem,*p2=L2.elem,*p3;
    p3=(elemtype*)malloc(L3->length*sizeof(elemtype)); //申请新的内存
    L3->elem=p3; 
    elemtype *p1_last,*p2_last;     //定义指向初地址和末地址的指针
    p1_last=L1.elem+L1.length-1;
    p2_last=L2.elem+L2.length-1;
    while (p1 <= p1_last && p2 <= p2_last) {
        if( *p1<=*p2 ) *p3++ = *p1++;
        else *p3++ = *p2++;
    }
    while(p1 <= p1_last) *p3++ = *p1++;
    while(p2 <= p2_last) *p3++ = *p2++;//判空，不为空继续赋值，直到指向最后指针。
    return *L3;
 } 
int main()
{
    sqlist LL;
    elemtype x,data;
    int r, i,j;
    if (!initlist(LL)) //初始化
        return error;
    printf("input data-->\n");       //创建 
    LL=creata_list(LL);
    
    printf("check Order table-->\n");       //显示 
    printlist(LL);

    printf("value index-->\n");  //插入
    scanf("%d %d", &x, &r);
    insertlist(LL, r, x);
    printlist(LL);

    printf("index-->\n");  //删除
    scanf("%d", &r);
    dellist(LL,r,x);
    printlist(LL);

    printf("input locate-->\n");
    scanf("%d",&j);
    data=LocatedList(LL,j);
    printf("the elem[%d] = %d\n",j,data);

    printf("input value-->\n");
    elemtype temp,place;
    scanf("%d",&temp);
    place=GetList(LL, temp);
    printf("%d = the elem[%d]\n",temp,place+1);


    sqlist La,Lb,Lc;                    //合并集合 
    printf("Create list La-->\n");
    initlist(La);
    La=creata_list(La);
    printf("check La\n");
    printlist(La);
    printf("Create list Lb-->\n");
    initlist(Lb);
    Lb=creata_list(Lb);
    printf("check Lb\n");
    printlist(Lb);

    printf("combine list-->\n");
                             //MergeList(La,Lb,&Lc);
    CombineList(La,Lb,&Lc);  //修改
    printlist(Lc);

    sqlist L1,L2,L3;                    //合并有序表
    printf("Create list L1-->\n");
    initlist(L1);
    L1=creata_list(L1);
    printf("check L1\n");
    printlist(L1);

    printf("Create list L2-->\n");
    initlist(L2);
    L2=creata_list(L2);
    printf("check L2\n");
    printlist(L2);

    printf("MergeList list-->\n");
    MergeList(L1,L2,&L3);
    printlist(L3);

    return 0;
}