C语言编程题 编写main函数，声明结构数组a、b并用测试数据初始化

#include <iostream>
#include <string.h>
#include <algorithm>

using namespace std;

 struct Stu{
     int id;
     char name[20];
     char sex[2];
 };
 void display(Stu stu[],int n)
 {
     printf("ID NAME SEX\n");
     int i;
     for(i=0;i<n;i++)
         printf("%d %s %s\n",stu[i].id,stu[i].name,stu[i].sex);
 }
 void del(Stu a[],Stu b[],int na,int nb)
 {
     int i,j,idx=-1;
     Stu temp[7];
     memset(temp,0x0,sizeof(temp));
     for(i=0;i<nb;i++)
         for(j=0;j<na;j++)
         {
             if(a[j].id == b[i].id && (strcmp(a[j].name,b[i].name)==0) && (strcmp(a[j].sex,b[i].sex)==0))
             {
                 idx = j;
                 break;
             }
         }
     if(idx != -1)
     {
         for(i=0;i<(na-1);i++)
         {
             if(i >= idx)
                a[i] = a[i+1];
         }
     }
     memset(&a[i],0x0,sizeof(a[i]));
 }

 bool cmp(Stu a,Stu b)
 {
     return a.id<b.id;
 }

 bool cmp2(Stu a,Stu b)
 {
     return (strcmp(a.name,b.name) < 0);
 }

 void merge(Stu a[],Stu b[],int na,int nb)
 {
     int i;
     for(i=0;i<na;i++)
         b[i+nb] = a[i];
     sort(b,b+(na+nb),cmp);
 }

void sort(Stu stu[],int n)
{
     sort(stu,stu+n,cmp2);
}

int main(){
    Stu a[7] = {{101, "tom","m"},{103,"mary","f"},{104,"mark","m"},
    {105,"julia","f"},{106, "sara","f"}},b[7]={{102, "mark","m"},{104,"mark","m"}};
    printf("a:\n");
    display(a,5);
    printf("\nb:\n");
    display(b,2);

    del(a,b,5,2);
    printf("\na:\n");
    display(a,4);

    merge(a,b,4,2);
    printf("\nb:\n");
    display(b,6);

    sort(a,4);
    printf("\na:\n");
    display(a,4);

    return 0;
}