网络编程day7

本文主要是介绍网络编程day7，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

思维导图

数据库编程实现学生管理系统

#include <header.h>
#define ID 1
#define NAME 2
#define AGE 3
#define SCORE 4
int do_add(sqlite3 *ppdb)
{int add_numb;char add_name[20];int add_age;double add_score;printf("enter student id:");scanf("%d",&add_numb);printf("enter student name:");scanf("%s",add_name);printf("enter student age:");scanf("%d",&add_age);printf("enter student score:");scanf("%lf",&add_score);getchar();char sql[128]="";snprintf(sql,sizeof(sql),"insert into stu values(%d,\"%s\",%d,%.2lf);",add_numb,add_name,add_age,add_score);char *errmsg=NULL;if(sqlite3_exec(ppdb,sql,NULL,NULL,&errmsg)!=SQLITE_OK){printf("stu create fail:%s\n",errmsg);sqlite3_free(errmsg);return 1;}printf("table stu create success\n");return 0;
}
int callback(void* arg,int cols,char** col_text,char** col_name)
{if(*(int *)arg==0){for(int i=0;i<cols;i++){printf("%s\t",col_name[i]);}printf("\n");*(int *)arg=1;}for(int i=0;i<cols;i++){printf("%s\t",col_text[i]);}printf("\n");return 0;
}
int do_select(sqlite3 *ppdb)
{int flag=0;char sql[128]="select * from stu;";char *errmsg=NULL;if(sqlite3_exec(ppdb,sql,callback,&flag,&errmsg)!=SQLITE_OK){printf("stu select fail:%s\n",errmsg);sqlite3_free(errmsg);return 1;}printf("select have done\n");return 0;
}
int do_select_2(sqlite3 *ppdb)
{char sql[128]="select * from stu;";char **pazresult=NULL;int cols=0;int rows=0;char *errmsg=NULL;if(sqlite3_get_table(ppdb,sql,&pazresult,&rows,&cols,&errmsg)!=SQLITE_OK){printf("stu select fail:%s\n",errmsg);sqlite3_free(errmsg);return 1;}for(int i=0;i<rows+1;i++){for(int j=0;j<cols;j++){printf("%s\t",pazresult[i*cols+j]);}printf("\n");}sqlite3_free_table(pazresult);return 0;
}
int do_delete(sqlite3 *ppdb)
{int id;printf("enter the student id u want to delete:");scanf("%d",&id);getchar();char sql[128]="";char *errmsg=NULL;snprintf(sql,sizeof(sql),"delete from stu where id=%d;",id);if(sqlite3_exec(ppdb,sql,NULL,NULL,&errmsg)!=SQLITE_OK){printf("stu delete fail:%s\n",errmsg);sqlite3_free(errmsg);return 1;}printf("delete have done\n");return 0;
}
int do_update(sqlite3 *ppdb)
{int id;int newid;char name[20];int age;double score;int column;printf("enter the id u want to update:");scanf("%d",&id);getchar();char sql[128]="";char *errmsg=NULL;printf("enter the column u want to update:");scanf("%d",&column);getchar();switch(column){case 1:{printf("enter the new id:");scanf("%d",&newid);getchar();snprintf(sql,sizeof(sql),"update stu set id = %d where id = %d;",newid,id);if(sqlite3_exec(ppdb,sql,NULL,NULL,&errmsg)!=SQLITE_OK){printf("stu update fail:%s\n",errmsg);sqlite3_free(errmsg);return 1;}printf("update have done\n");}break;case 2:{printf("enter the new name:");scanf("%s",name);getchar();snprintf(sql,sizeof(sql),"update  stu set name = \"%s\" where id = %d ;",name,id);if(sqlite3_exec(ppdb,sql,NULL,NULL,&errmsg)!=SQLITE_OK){printf("stu update fail:%s\n",errmsg);sqlite3_free(errmsg);return 1;}printf("update have done\n");}break;case 3: 		{printf("enter the new age:");scanf("%d",&age);getchar();snprintf(sql,sizeof(sql),"update  stu set age = %d where id = %d;",age,id);if(sqlite3_exec(ppdb,sql,NULL,NULL,&errmsg)!=SQLITE_OK){printf("stu update fail:%s\n",errmsg);sqlite3_free(errmsg);return 1;}printf("update have done\n");}break;case 4:{printf("enter the new score:");scanf("%lf",&score);getchar();snprintf(sql,sizeof(sql),"update stu set score = %.2lf  where id = %d;",score,id);if(sqlite3_exec(ppdb,sql,NULL,NULL,&errmsg)!=SQLITE_OK){printf("stu update fail:%s\n",errmsg);sqlite3_free(errmsg);return 1;}printf("update have done\n");}break;default:printf("argument error\n");break;}return 0;
}int main(int argc, const char *argv[])
{sqlite3 *ppdb=NULL;if(sqlite3_open("02.db",&ppdb)!=SQLITE_OK){printf("open error:%d,%s\n",sqlite3_errcode(ppdb),sqlite3_errmsg(ppdb));return 1;}printf("the sqlite has been opened\n");char sql[128]="create table if not exists stu(id int,name text,age int,score real);";char *errmsg=NULL;if(sqlite3_exec(ppdb,sql,NULL,NULL,&errmsg)!=SQLITE_OK){printf("stu create fail:%s\n",errmsg);sqlite3_free(errmsg);return 1;}printf("table stu create success\n");int menu=0;while(1){system("clear");printf("\t\t========student information mange system===========\n");printf("\t\t=============   1.add  ================\n");printf("\t\t=============  2.delete ================\n");printf("\t\t=============  3.update   ================\n");printf("\t\t=============  4.select  ================\n");printf("\t\t=============   5.exit     ================\n");printf("enter ur choice:");scanf("%d",&menu);getchar();switch (menu){case 1:{do_add(ppdb);}break;case 2:{do_delete(ppdb);}break;case 3:{do_update(ppdb);}break;case 4:{//do_select(ppdb);do_select_2(ppdb);}break;case 5:goto END;default:printf("error argument\n");}printf("enter \"enter\" to clear the scream\n");while(getchar()!='\n');}
END:sqlite3_close(ppdb);return 0;
}

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