diff --git a/7.c b/7.c
new file mode 100644
index 0000000..c556108
--- /dev/null
+++ b/7.c
@@ -0,0 +1,154 @@
+#include <stdio.h>
+#include <string.h>
+
+struct student{
+	int n;
+	int c;
+	char l[8];
+	float m;
+	float p;
+	float e;
+	float s;
+}stu[7]={{10001,11,"Zhang",99.5,88.5,89.5},{10002,12,"Yang",77.9,56.5,87.5},{10003,11,"Liang",92.5,99.0,60.5},{10004,11,"Cai",89.6,56.9,90.5},{10005,14,"Fu",55.6,67.9,98.9},{10006,12,"Mao",22.1,45.9,99.2},{10007,13,"Zhan",35.6,67.0,88.0}};
+//求和函数 
+void sum(struct student stu[7])
+{
+	int i;
+	for(i=0;i<7;i++)
+	{
+		stu[i].s=stu[i].m+stu[i].p+stu[i].e;
+	}
+}
+// 排序函数 
+void sort(struct student stu[],int len)
+{
+	int i,j;
+	for(i=0;i<len;i++)
+	{
+		int k=i;
+		for(j=i;j<len;j++)
+		{
+			if(stu[k].c>stu[j].c||(stu[k].c==stu[j].c&&stu[k].s<stu[j].s))
+			{
+				k=j;
+			}
+			if(k!=i)
+			{
+				struct student temp=stu[i];
+				stu[i]=stu[k];
+				stu[k]=temp;
+			}
+		}
+	}
+	for(i=0;i<len;i++)
+	{
+	printf("%d %d %s %.1f %.1f %.1f \n",stu[i].n,stu[i].c,stu[i].l,stu[i].m,stu[i].p,stu[i].e);
+	}
+}
+
+void class(int a,int b)
+{
+	struct student temp[7];
+	int i,j=0;
+	for(i=0;i<7;i++)
+	{
+		if(a<=stu[i].c&&stu[i].c<=b)
+		temp[j++]=stu[i];
+	}
+	sort(temp,j);  	
+} 
+void number(int a,int b)
+{
+	struct student temp[7];
+	int i,j=0;
+	for(i=0;i<7;i++)
+	{
+		if(a<=stu[i].n&&stu[i].n<=b)
+		temp[j++]=stu[i];
+	}
+	sort(temp,j);  	
+} 
+void name(const char* prefix)
+{
+    struct student temp[7];
+    int i,j = 0;
+    for (i = 0; i < 7; i++)
+    {
+        if (strncmp(prefix, stu[i].l, strlen(prefix)) == 0)
+            temp[j++] = stu[i];
+    }
+    sort(temp, j);
+}
+
+void score(int a)
+{
+	struct student temp[7];
+	int i,j=0;
+	for(i=0;i<7;i++)
+	{
+		if(a<=stu[i].s)
+		temp[j++]=stu[i];
+	}
+	sort(temp,j);	
+} 
+void candn(int a,int b,int c)
+{
+	struct student temp1[7],temp2[7];
+	int i,j=0;
+	for(i=0;i<7;i++)
+	{
+		if(a==stu[i].c)
+		temp1[j++]=stu[i];
+	}
+	int len=j-1;
+	for(i=0,j=0;i<len;i++)
+	{
+		if(b<=temp1[i].n&&temp1[i].n<=c)
+		temp2[j++]=temp1[i];
+	}
+	
+	sort(temp2,j);  	
+} 
+
+
+int main()
+{
+	sum(stu);
+	char gets=getchar();
+	//查班级 
+	if(gets=='1')
+	{
+		int a,b;
+		scanf("%d-%d",&a,&b);
+		class(a,b);
+	}
+	//查学号 
+	if(gets=='2')
+	{
+		int a,b;
+		scanf("%d-%d",&a,&b);
+		number(a,b);
+	}
+	//查姓名 
+	if (gets=='3')
+    {
+        char prefix[8];
+        scanf("%s", prefix);
+        name(prefix);
+    }
+	//查分数 
+	if(gets=='4')
+	{
+		int a;
+		scanf("%d",&a);
+		score(a);
+	}
+	//查班级和学号 
+	if(gets=='5')
+	{
+		int a,b,c;
+		scanf("%d.%d-%d",&a,&b,&c);
+		candn(a,b,c);
+	}
+	
+}