diff --git a/main.c b/main.c
new file mode 100644
index 0000000..d245c25
--- /dev/null
+++ b/main.c
@@ -0,0 +1,325 @@
+#include <stdio.h>
+#include <string.h>
+#pragma warning (disable:4996)
+
+typedef struct Student
+{
+	char id[20];
+	char clas[20];
+	char name[20];
+	double score1;
+	double score2;
+	double score3;
+	double score;
+}Student;
+
+Student stu[50]={{"10001","11","Zhang",99.5,88.5,89.5,277.5},{"10002","12","Yang",77.9,56.5,87.5,221.9},{"10003","11","Liang",92.5,99.0,60.5,252.0}};
+                         
+
+void start()
+{
+	printf("\n以下为主菜单：\n");
+    printf("                              1.input\n");
+    printf("                              2.delete\n");
+    printf("                              3.select\n");
+    printf("                              4.order\n");
+	printf("                              5.output\n");
+	printf("                              6.quit\n");
+    printf("please input your option：\n");
+}//开始显示主菜单的函数
+
+void input()
+{   int i;int flag=1;
+    int len=lens(stu);
+    scanf("%s %s %s %lf %lf %lf", stu[len].id,stu[len].clas,&stu[len].name,&stu[len].score1, &stu[len].score2, &stu[len].score3);
+    char nul3=getchar();
+    stu[len].score = stu[len].score1 + stu[len].score2 + stu[len].score3;
+    for(i=0;i<len;i++)
+    {
+        if(strcmp(stu[len].id,stu[i].id)==0)
+        {
+            flag=0;
+            stu[i]=stu[len];
+        } 
+    }
+    if(flag==1)
+    {
+        for( i=0;i<len;i++)
+        {
+              printf("%s %s %s %.2f %.2f %.2f %.2f\n",stu[i].id,stu[i].clas,stu[i].name,stu[i].score1,stu[i].score2,stu[i].score3,stu[i].score);
+        }
+    }
+    if(flag==0)
+    {
+        for( i=0;i<len;i++)
+        {
+			if((strcmp(stu[len].id,stu[i].id)==0))
+            printf("%s %s %s %.2f %.2f %.2f %.2f\n",stu[i].id,stu[i].clas,stu[i].name,stu[i].score1,stu[i].score2,stu[i].score3,stu[i].score);
+            else if((strcmp(stu[len].id,stu[i].id)!=0))
+            printf("%s %s %s %.2f %.2f %.2f %.2f\n",stu[i].id,stu[i].clas,stu[i].name,stu[i].score1,stu[i].score2,stu[i].score3,stu[i].score);
+        }
+        stu[len].id[0] ='0';
+		stu[len].id[1] ='0';
+		stu[len].id[2] ='0';
+		stu[len].id[3] ='0';
+		stu[len].id[4] ='0';
+		stu[len].score1=0;
+		stu[len].score2=0;
+		stu[len].score3=0;
+		stu[len].score = 0;
+    }
+}   //向新的空间输入或者可以在输入id相同时对前面的数据修改 
+
+void output()
+{
+	int len=lens(stu);
+    double temp;
+    int i,j;
+    for (i = 0; i < 2; i++)
+    {
+        for (j = 0; j < 2 - i; j++)
+        {
+            if (stu[j].score > stu[j + 1].score)
+            {
+                Student temp = stu[j];
+                stu[j] = stu[j + 1];
+                stu[j + 1] = temp;
+            }
+        }
+    }
+    for( i=0;i<len;i++)
+    {
+    	printf("%s %s %s %.2f %.2f %.2f %.2f\n",stu[i].id,stu[i].clas,stu[i].name,stu[i].score1,stu[i].score2,stu[i].score3,stu[i].score);
+	}
+}     //按总分从小到大输出 
+
+int  lens(Student stu[])
+{
+	int i;
+    int court = 0;
+    for (i = 0;i < 50;i++)
+    {
+        if (stu[i].score3 > 0)
+        {
+            court++;
+        }
+        if(stu[i].score3 <= 0)
+        {
+        	break;
+		}
+    }
+    return court;
+}     //测学生数量 
+
+void order()
+{
+	int i,j,k;
+    int a[100] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 };
+    int c[100] = { 0 };
+    int number = 0;
+    int len = lens(stu);
+    for (i = 0;i < len;i++)
+    {
+        stu[i].score = stu[i].score1 + stu[i].score2 + stu[i].score3;
+    }
+    stu[len + 1].score = 0;
+    for (i = 0;i < len;i++)
+    {
+        for (j = 0;j < len - i-1;j++)
+        {
+            if (strcmp(stu[j].clas, stu[j + 1].clas) > 0)
+            {
+                stu[len + 1] = stu[j];
+                stu[j] = stu[j + 1];
+                stu[j + 1] =stu[len + 1];
+            }
+        }
+    }
+    
+    stu[len].score = 6458;
+    for (i = 0;i < len;i++)
+    {
+        if (stu[i].score == stu[i + 1].score)
+        {
+            a[number]++;
+        }
+        if (stu[i].score != stu[i + 1].score)
+        {
+            a[number]++;
+            c[number + 1] = i + 1;
+            number++;
+        }
+    }
+    for (k = 0;k < number;k++)
+    {
+
+        for (i = 0;i < a[k];i++)
+        {
+            for (j = c[k];j < a[k] - i;j++)
+            {
+                if (stu[j].score < stu[j + 1].score)
+                {
+                    stu[len + 1] = stu[j];
+                    stu[j] = stu[j + 1];
+                    stu[j + 1] = stu[len + 1];
+                }
+            }
+        }
+    }
+    for (i = 0;i < len;i++)
+    {
+            printf("%s %s %.2f %.2f %.2f %.2f\n", stu[i].id, stu[i].clas, stu[i].score1, stu[i].score2, stu[i].score3, stu[i].score);
+	}
+}		//先按班级再按成绩排序 
+
+void delete() 
+{
+    int len = lens(stu);int flag = 0;
+    int i,j,k;
+    printf("请输入要删除学生的学号或者姓名：\n");
+    char a[10];//用来储存学号或者名字
+    scanf("%s", a);
+    char nul2=getchar();
+    for (i = 0;i < len;i++)
+    {
+        if (strcmp(a, stu[i].id) == 0 || strcmp(a, stu[i].name) == 0)
+        {
+            flag = 1;//有的话删除并输出
+            for (k = i + 1;k < len;k++)
+            {
+                stu[k - 1] = stu[k];//相当于删除
+            }
+
+
+        }
+    }
+    if (flag == 0)//没有的话输出原来的数据
+    {
+        for (j = 0;j < len;j++)
+        {
+            printf("%s %s %s %.2f %.2f %.2f %.2f\n", stu[j].id,stu[j].clas, stu[j].name, stu[j].score1, stu[j].score2, stu[j].score3, stu[j].score);
+        }
+
+    }
+    if (flag == 1)//有的话输出这个之外的（已删除这个学生）
+    {
+        len = lens(stu) - 1;
+        for (j = 0;j < len;j++)
+        {
+            printf("%s %s %s %.2f %.2f %.2f %.2f\n", stu[j].id,stu[j].clas, stu[j].name, stu[j].score1, stu[j].score2, stu[j].score3, stu[j].score);
+        }
+    }
+} //删除 
+
+void select(char* a,char* b,int i,double k)
+{
+	int len = lens(stu),j;
+	if (i == 1)
+	{
+		for (j = 0;j < len;j++)
+		{
+			if (strcmp(stu[j].clas,a)>=0 && strcmp(stu[j].clas,b)<=0)
+			{
+				printf("%s %s %s %.2f %.2f %.2f %.2f\n", stu[j].id, stu[j].clas, stu[j].name, stu[j].score1, stu[j].score2, stu[j].score3, stu[j].score);
+			}
+		}
+	}
+	else if (i == 2)
+	{
+		for (j = 0;j < len;j++)
+		{
+			if (strcmp(stu[j].id,a)>=0 && strcmp(stu[j].id,b)<=0)
+			{
+				printf("%s %s %s %.2f %.2f %.2f %.2f\n", stu[j].id, stu[j].clas, stu[j].name, stu[j].score1, stu[j].score2, stu[j].score3, stu[j].score);
+			}
+		}
+	}
+	else if (i == 3)
+	{
+		for (j = 0;j < len;j++)
+		{
+			if(strcmp(stu[j].name,a)>=0 && strcmp(stu[j].name,b)<=0)
+			{
+				printf("%s %s %s %.2f %.2f %.2f %.2f\n", stu[j].id, stu[j].clas, stu[j].name, stu[j].score1, stu[j].score2, stu[j].score3, stu[j].score);
+			}
+		}
+	}
+	else if (i == 4)
+	{
+		for (j = 0;j < len;j++)
+		{
+			if (stu[j].score>=k)
+			{
+				printf("%s %s %s %.2f %.2f %.2f %.2f\n", stu[j].id, stu[j].clas, stu[j].name, stu[j].score1, stu[j].score2, stu[j].score3, stu[j].score);
+			}
+		}
+	}
+}   //a表示初始，b表示末尾
+
+
+int main()
+{
+	while(1)
+	{
+		start();
+		char g = getchar();
+		char nul=getchar();
+		if (g == '1')
+		{
+			printf("Please input info of a student（格式为id clas name score1 score2 score3）:\n");
+			input();
+		}
+		else if(g=='4')
+		{
+			order();
+		}	
+		else if(g=='5')
+		{
+			output();
+		}
+		else if(g=='2')
+		{
+			delete();
+		}
+		else if(g=='3')
+		{
+			char a[20],b[20];
+			int t;
+			double k; 
+			printf("选择筛选的方式\n1.按班级\n2.按学号\n3.按姓名\n4.按总分\n");
+			scanf("%d",&t);
+			nul=getchar();
+			if(t>=1&&t<=3)
+			{
+				printf("请输入要求的范围：\nbegin：");
+				scanf("%s",a);
+				printf("end：");
+				scanf("%s",b);
+				nul=getchar();
+				select(a,b,t,0);
+			}
+			else if(t==4)
+			{
+				printf("请输入要大于等于的总分\n");
+				scanf("%lf\n",k);
+				nul=getchar();
+				select(a,b,t,k);
+			}
+		}
+		else if(g=='6')
+		{
+			break;
+		}
+		else printf("输入错误");
+		printf("continue?\n");
+		char s[100];
+		scanf("%s",s);
+		nul=getchar();
+		char* yes="yes";
+		if(strcmp(s,yes)==0){}
+		else break; 
+	}
+    return 0;
+}
+
+