C++用mysql自带的头文件连接数据库

#include <mysql/mysql.h>
#include <stdio.h>
#include<iostream>
#include<fstream>
#include<string.h>
using namespace std;
MYSQL *conn;
 MYSQL_RES *res;
 MYSQL_ROW row;
 
class people
{
public:
  char name[20];
  int pid;
  int type;
  char phone[30];
public:
  people(int a){};
  people(){
    setall();
  };
  ~people(){};
public:
  void setall();
 
};
 
void people::setall()
{
  cout<<"请输入该用户的编号"<<endl;
  cin>>pid;
  cout<<"请输入该用户的名字"<<endl;
// gets(name);
  cin>>name;
  cout<<"请输入该用户的类型"<<endl;
  cin>>type;
  cout<<"请输入该用户的联系方式"<<endl;
  cin>>phone;
 
}
void save()
{
  char sql[1000];
  people a;
  sprintf(sql,"insert into student values(%d,'%s',%d,'%s')",a.pid,a.name,a.type,a.phone);
  if(mysql_query(conn,sql))
    {
      printf("添加失败: (%s)n",mysql_error(conn));
      return;
    }
    else
    {
      printf("添加成功!n");
      return;
    }
  return;
}
void update(){
  char sql[1000];
  people a(1);
  cout<<"请输入你要更改的用户的编号:";
  cin >> a.pid;
  cout<<"请输入你要此编号用户的姓名：";
  cin >> a.name;
  cout <<"请输入你要更改的用户的类型：";
  cin >> a.type;
  cout << "请输入你要更改的用户的电话：";
  cin >> a.phone;
  sprintf(sql,"update student set name = '%s',usetype=%d,phone='%s' where pid = %d",a.phone,a.pid);
    if(mysql_query(conn,sql))
      {
        printf("更改失败： (%s)n",mysql_error(conn));
        return;
      }
      else
      {
        printf("更改成功!n");
        return;
      }
    return;
}
void del()
{
  char sql[1000];
  int pid;
  cout<<"请输入你要删除的人的编号"<<endl;
  cin>>pid;
  sprintf(sql,"delete from student where pid = %d",pid);
  if(mysql_query(conn,sql))
    {
      printf("删除 失败(%s)n",mysql_error(conn));
      return;
    }
    else
    {
      printf("删除成功!n");
      return;
    }
  return;
}
void menu()
{
  cout<<"1.用户录入"<<endl;
  cout<<"2.显示"<<endl;
  cout<<"3.更改"<<endl;
  cout<<"4.删除"<<endl;
  cout<<"5.退出"<<endl;
}
void show()
{
   if (mysql_query(conn,"select * from student")) {
     fprintf(stderr,"%sn",mysql_error(conn));
     return;
    }
    res = mysql_use_result(conn);
 
    printf("编号t名字t类型t联系方式n");
    while ((row = mysql_fetch_row(res)) != NULL){
     cout<<row[0]<<"t"<<row[1]<<"t"<<row[2]<<"t"<<row[3]<<endl;
    }
    mysql_free_result(res);
 
}
int main() {
  int s;
  conn = mysql_init(NULL);
  if (!mysql_real_connect(conn,"localhost","root","abc",NULL,0)) {
   fprintf(stderr,mysql_error(conn));
   return -1;
  }
  mysql_query(conn,"set names utf8");
  while(true){
    menu();
    cin>>s;
    if(s==2){show();}
    if(s==1){save();}
    if(s==3){update();}
    if(s==4){del();}
    if(s==5){mysql_close(conn);return 0;}
    cout<<"按任意键继续.."<<endl;
    getchar();
  }
  return 0;
}