diff --git a/c3.cpp b/c3.cpp
new file mode 100644
index 0000000..8216fcc
--- /dev/null
+++ b/c3.cpp
@@ -0,0 +1,111 @@
+#include"c1.cpp"
+void section()                //学生成绩分段
+{
+	system("cls");
+	int k=0;
+	double c;
+	if((fp=fopen("a.txt","r"))==NULL)
+	{
+	printf("Cannot open the file!\n");
+
+	}
+	while(fscanf(fp,"%lf%s%f",&s[k].no,s[k].name,&s[k].cscore)!=EOF)
+	{
+	k++;
+	}
+	printf("\t\t\t  90分以上学生的信息!\n");
+	for(i=0;i<k;i++)
+		if(s[i].cscore>=90)
+			printf("\t\t\t%.0lf %s %.1f\n",s[i].no,s[i].name,s[i].cscore);
+			printf("\n\n");
+	printf("\t\t\t  80到89分学生的信息!\n");
+	for(i=0;i<k;i++)
+		if(s[i].cscore<90&&s[i].cscore>=80)
+			printf("\t\t\t%.0lf %s %.1f\n",s[i].no,s[i].name,s[i].cscore);
+			printf("\n\n");
+	printf("\t\t\t  60到79分学生的信息!\n");
+	for(i=0;i<k;i++)
+		if(s[i].cscore>=60&&s[i].cscore<80)
+			printf("\t\t\t%.0lf %s %.1f\n",s[i].no,s[i].name,s[i].cscore);
+			printf("\n\n");
+	printf("\t\t\t  60分以下学生的信息!\n");
+	for(i=0;i<k;i++)
+		if(s[i].cscore<60)
+		printf("\t\t\t%.0lf %s %.1f\n",s[i].no,s[i].name,s[i].cscore);
+		printf("\n\n");
+}
+void rank()                       //成绩的排序
+{
+	Student t;
+	int k=0;
+	double sum=0,j=0;
+	system("cls");
+	if((fp=fopen("a.txt","r"))==NULL)
+	{
+ 	printf("Cannot open the file!\n");
+
+	}
+	while(fscanf(fp,"%lf%s%f",&s[k].no,s[k].name,&s[k].cscore)!=EOF)
+	{
+	k++;
+	}
+	for(i=0;i<k;i++)
+		for(int j=i+1;j<k+1;j++)
+			if(s[i].cscore<s[j].cscore)
+			{t=s[i];s[i]=s[j];s[j]=t;}
+			for(i=0;i<k;i++)
+			{
+	  		if(s[i].cscore>=60)
+	  		j++;
+	  		}
+			for(i=0;i<k;i++)
+			sum=sum+s[i].cscore;
+			for(i=0;i<k;i++)
+			printf("\t\t\t第%d名:%.0lf  %-4s %.1f\n",i+1,s[i].no,s[i].name,s[i].cscore);
+			printf("\t\t\t最高分:%.1lf\n",s[0].cscore);
+			printf("\t\t\t最低分:%.1lf\n",s[k-1].cscore);
+			printf("\t\t\t及格率:%.2lf\n",j/k);
+			printf("\t\t\t平均分:%.2lf\n",sum/k);
+}
+void choose(int n)              //目录的选项
+{
+	system("cls");
+	int y; 
+	switch(n)
+	{
+	case 1:input();
+		printf("\n\n\n\n\t\t\t是否返回？输入1表返回，输入2表退出！\n");
+		scanf("%d",&y);
+		if(y==1)
+		choose(fun());break;
+	case 2:output();
+		printf("\n\n\n\n\t\t\t是否返回？输入1表返回，输入2表退出！\n");
+		scanf("%d",&y);
+		if(y==1)
+		choose(fun());break;
+	case 3:modify();
+		printf("\n\n\n\n\t\t\t是否返回？输入1表返回，输入2表退出！\n");
+		scanf("%d",&y);
+		if(y==1)
+		choose(fun());break;
+	case 4:lookat();
+		printf("\n\n\n\n\t\t\t是否返回？输入1表返回，输入2表退出！\n");
+		scanf("%d",&y);
+		if(y==1)
+		choose(fun());break;
+	case 5:section();
+		printf("\n\n\n\n\t\t\t是否返回？输入1表返回，输入2表退出！\n");
+		scanf("%d",&y);
+		if(y==1)
+		choose(fun());break;
+	case 6:rank();
+		printf("\n\n\n\n\t\t\t是否返回？输入1表返回，输入2表退出！\n");
+		scanf("%d",&y);
+		if(y==1)
+		choose(fun());break;
+	case 7:exit(0);break;
+	default:printf("\n\n\t\t\t   输入没有的选项，请重新输入！\n");
+		choose(fun());
+	}	
+} 
+