diff --git a/a7.c b/a7.c
new file mode 100644
index 0000000..0995b76
--- /dev/null
+++ b/a7.c
@@ -0,0 +1,152 @@
+#include <stdio.h>
+#include <string.h>
+struct stu {
+    char num[6];
+    char class[3];
+    char name[6];
+    float grade1;
+    float grade2;
+    float grade3;
+    float grade;
+}s[10],ss,sss[7];
+void f1(struct stu s[],int k)
+{
+	for(int i=0;i<k-1;i++)
+	{
+	    for(int j=i+1;j<k;j++)
+	    {
+	    	if(strcmp(s[i].class,s[j].class)>0)
+	    	{
+	    		ss=s[i];
+	    		s[i]=s[j];
+	    		s[j]=ss;
+			}		
+		}
+	}
+}
+void f2(struct stu s[])
+{
+	for(int o=11;o<=14;o++)
+	{
+	for(int i=0;s[i].class==o;i++)
+	{
+	    for(int j=i+1;s[j].class==o;j++)
+	    {
+	    	if(s[i].grade<s[j].grade)
+	    	{
+	    		ss=s[i];
+	    		s[i]=s[j];
+	    		s[j]=ss;
+			}		
+		}
+	}
+    }   
+}
+void f3(struct stu s[],int k)
+{
+
+	for(int i=0;i<k;i++)
+	{
+	     printf("%s %s %s %.1f %.1f %.1f\n",s[i].num,s[i].class,s[i].name,s[i].grade1,s[i].grade2,s[i].grade3);
+    }
+}
+int main()
+{
+	strcpy(s[0].num,"10001");strcpy(s[0].class,"11");strcpy(s[0].name,"Zhang");s[0].grade1=99.5;s[0].grade2=88.5;s[0].grade3=89.5;s[0].grade=s[0].grade1+s[0].grade2+s[0].grade3;
+	strcpy(s[1].num,"10002");strcpy(s[1].class,"12");strcpy(s[1].name,"Yang");s[1].grade1=77.9;s[1].grade2=56.5;s[1].grade3=87.5;s[1].grade=s[1].grade1+s[1].grade2+s[1].grade3;
+	strcpy(s[2].num,"10003");strcpy(s[2].class,"11");strcpy(s[2].name,"Liang");s[2].grade1=92.5;s[2].grade2=99.0;s[2].grade3=60.5;s[2].grade=s[2].grade1+s[2].grade2+s[2].grade3;
+	strcpy(s[3].num,"10004");strcpy(s[3].class,"11");strcpy(s[3].name,"Cai");s[3].grade1=89.6;s[3].grade2=56.9;s[3].grade3=90.5;s[3].grade=s[3].grade1+s[3].grade2+s[3].grade3;
+	strcpy(s[4].num,"10005");strcpy(s[4].class,"14");strcpy(s[4].name,"Fu");s[4].grade1=55.6;s[4].grade2=67.9;s[4].grade3=98.9;s[4].grade=s[4].grade1+s[4].grade2+s[4].grade3;
+	strcpy(s[5].num,"10006");strcpy(s[5].class,"12");strcpy(s[5].name,"Mao");s[5].grade1=22.1;s[5].grade2=45.9;s[5].grade3=99.2;s[5].grade=s[5].grade1+s[5].grade2+s[5].grade3;
+	strcpy(s[6].num,"10007");strcpy(s[6].class,"13");strcpy(s[6].name,"Zhan");s[6].grade1=35.6;s[6].grade2=67.9;s[6].grade3=88.0;s[6].grade=s[6].grade1+s[6].grade2+s[6].grade3;
+	int a;
+	scanf("%d",&a);
+	if(a==1)
+	{
+		char aa[3],bb[3];
+	    scanf("%s %s",aa,bb);
+	    int k=0;
+	    for(int i=0;i<7;i++)
+     	{
+		if(strcmp(s[i].class,aa)>=0&&strcmp(s[i].class,bb)<=0)
+		{
+			sss[k]=s[i];
+			k++;
+		}
+	    }
+	    f1(sss,k);
+	    f2(sss);
+	    f3(sss,k);
+	}
+	else if(a==2)
+	{
+		char cc[6],dd[6];
+		scanf("%s %s",cc,dd);
+		int k=0;
+	    for(int i=0;i<7;i++)
+     	{
+		   if(strcmp(s[i].num,cc)>=0&&strcmp(s[i].num,dd)<=0)
+		   {
+			  sss[k]=s[i];
+			  k++;
+		   }
+	    }
+	    f1(sss,k);
+	    f2(sss);
+	    f3(sss,k);
+	}
+	else if(a==3)
+	{
+		char hh[10];
+		scanf("%s",hh);
+		int len=strlen(hh);
+		int k=0;
+		for(int i=0;i<7;i++)
+		{
+	       if(strncmp(hh,s[i].name,len-1)==0)
+	       {
+	       	sss[k]=s[i];
+	       	k++;
+		   }
+	    }
+		f1(sss,k);
+	    f2(sss);
+	    f3(sss,k);
+	}
+	else if(a==4)
+	{
+		double d;
+		scanf("%lf",&d);
+		int k=0;
+	    for(int i=0;i<7;i++)
+     	{
+		   if(s[i].grade>=d)
+		   {
+			  sss[k]=s[i];
+			  k++;
+		   }
+	    }
+	    f1(sss,k);
+	    f2(sss);
+	    f3(sss,k);
+	}
+	
+	else if(a==5)
+	{
+		char ee[3],ff[6],gg[6];
+		scanf("%s%s%s",ee,ff,gg);
+		int k=0;
+		 for(int i=0;i<7;i++)
+     	{
+		   if(strcmp(s[i].class,ee)==0&&strcmp(s[i].num,ff)>=0&&strcmp(s[i].num,gg)<=0)
+		   {
+			  sss[k]=s[i];
+			  k++;
+		   }
+	    }
+	    f1(sss,k);
+	    f2(sss);
+	    f3(sss,k);
+	}
+	return 0;
+}
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