diff --git a/main.c b/main.c
index 87fc29c..9b342e3 100644
--- a/main.c
+++ b/main.c
@@ -1,9 +1,11 @@
 #include <stdio.h>
+#include<stdlib.h>
+#include<time.h>
 
 struct Student 
 {
 	char cSchool[15];
-    char cGrade[15];
+	char cGrade[15];
 	char cName[15];		
 };
 
@@ -16,7 +18,7 @@ int k=0,grade;           /*
 
 int main()
 {
-   	struct Student student1;
+	struct Student student1;
 	printf("****预祝测试顺利****\n\n");
 	printf("学校:");
 	scanf("%s",&student1.cSchool);
@@ -24,10 +26,10 @@ int main()
 	scanf("%s",&student1.cGrade);
 	printf("姓名:");
 	scanf("%s",&student1.cName);
-    printf("\n");
-	 
-    printf("请回答下面十道题目\n");
-	
+	printf("\n");
+
+	printf("请回答下面十道题目\n");
+
 	do{
 		int i=test();
 		if(i==-1)
@@ -39,7 +41,7 @@ int main()
 			else if(grade>=70&&grade<80)
 				printf("-------OK");
 			else if(grade>=60&&grade<70)
-			    printf("-------PASS");
+				printf("-------PASS");
 			else
 				printf("-------TRY AGAIN");	
 			break;
@@ -65,17 +67,17 @@ int test()
 	{
 		printf("\n所有题目已答完，你的成绩：%d分",grade); 
 		return -1;
-		}
+	}
 	else if(c==0)
 	{
 		printf("第%d题:%d+%d=",k,a,b);
 		return a+b; 
-		}
+	}
 	else if(c==1)
 	{
 		printf("第%d题:%d-%d=",k,a,b);
 		return a-b;
-		}
+	}
 	return -1;	
 }
 
@@ -85,41 +87,42 @@ int checknum(int a,int b)			/*
 		return 0;
 	else
 		return 1;
- } 
- 
- int checkresult(int result)
- {
-    int i;
-    for(i=1;i<4;i++)
+} 
+
+int checkresult(int result)
+{
+	int i;
+	for(i=1;i<4;i++)
 	{
-        scanf("%d", &x);
-        if (x!=result)
+		scanf("%d", &x);
+		if (x!=result)
 		{
-            if (i==3)
+			if (i==3)
 			{
-                if (c==0){
-                    printf("三次回答错误，正确答案是%d\n",a+b);
-                }
-                else {
-                    printf("三次回答错误，正确答案是%d\n",a-b);
-                }
-                return 0;
-            }
-            printf("回答错误,请再次输入：");
-        }
+				if (c==0){
+					printf("三次回答错误，正确答案是%d\n",a+b);
+				}
+				else {
+					printf("三次回答错误，正确答案是%d\n",a-b);
+				}
+				return 0;
+			}
+			printf("回答错误,请再次输入：");
+		}
 		else{
 			switch(i){
-						case 1:grade+=10;
-								break;
-						case 2:grade+=7;
-								break;
-						case 3:grade+=5;
-								break;
-						default:grade+=0;
-								break;
-				     }
-		    		 return 0;    		     
+			case 1:grade+=10;
+				break;
+			case 2:grade+=7;
+				break;
+			case 3:grade+=5;
+				break;
+			default:grade+=0;
+				break;
 			}
+			return 0;    		     
+		}
 	}
 	return 0;
- }
+}
+