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main.cpp

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+#define  _CRT_SECURE_NO_WARNINGS
+#include <iostream>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+using namespace std;
+
+typedef struct
+{
+    char name[20];         //名字
+    char number[20];       //学号
+    float Usualgrades;     //平时成绩
+    float Experimentalscore;//实验成绩
+    float Finalgrade;      //期末成绩
+    float Overallresult;    //总成绩
+}SS;
+
+SS* stu;
+
+void sortScore(SS stu[], int N);
+SS* readdatafromthefile(int *N);        //读取学生基本数据
+void Calculatinggrades(SS stu[], int N);//计算N个学生各自总成绩
+void Ranking(SS stu[], int N);          //根据总评成绩排名
+void Putout(SS stu[], int N);           //按照一定的格式输出N个学生的完整信息
+void searchstudent(SS stu[], int N);    //通过学号找到学生的基本信息
+void Meanandstandarddeviation(SS stu[],int N);
+void searchfor(SS stu[],int N);
+
+int main()
+{
+	cout << "       Student achievement management analysis system      " << endl;
+	cout << "-----------------------------------------------------------" << endl;
+	int N=0;
+	SS  *mate=NULL;
+	mate=readdatafromthefile(&N);
+	Calculatinggrades(mate,N);
+	sortScore(mate,N);
+	Putout(mate,N);
+	Meanandstandarddeviation(mate,N);
+	searchfor(mate,N);
+	free(mate);
+	system("pause");
+	return 0;
+}
+
+SS* readdatafromthefile(int *N)
+{
+    int n=0;
+	cout << "\nStep 1: Read the student's grade information from the file\n" << endl;
+    SS *stu;
+	FILE *fp=NULL;
+	fp=fopen("score.txt", "r");
+	stu=(SS*)malloc(sizeof(SS));
+	while((!feof(fp)))//读取每条学生的信息,其中feof的作用是:文件结束：返回非0值，文件未结束，返回0值
+	{
+		fscanf(fp,"%s%s%f%f%f\n",(stu[n].name),(stu[n].number),&stu[n].Usualgrades,&stu[n].Experimentalscore,&stu[n].Finalgrade);
+		printf("name:%s number:%s   Usual grades:%4.2f  Experimental score:%4.2f    Final grade:%4.2f \n", (stu[n].name),(stu[n].number), stu[n].Usualgrades, (stu[n].Experimentalscore),stu[n].Finalgrade);
+		n++;
+	}
+	*N=n;
+	printf("The number of the students are %d\n", n);
+	fclose(fp);
+	return stu;
+}
+
+void Calculatinggrades(SS stu[], int N)//计算N个学生各自的总评成绩
+{
+    int i;
+	cout << "\nStep 2: Calculate the total score of each student\n" << endl;
+	for(i=0;i<N;i++)
+	{
+        stu[i].Overallresult=0.2*stu[i].Usualgrades+0.2*stu[i].Experimentalscore+0.6*stu[i].Finalgrade;
+		printf("name:%s     number:%s     Overall result:%4.2f\n",(stu[i].name),(stu[i].number),stu[i].Overallresult);
+	}
+}
+
+int Ranking(const void *a, const void *b)//根据总评成绩排名
+{
+
+	SS *aa = (SS *)(a);
+	SS *bb = (SS *)(b);
+	if ((*aa).Overallresult < (*bb).Overallresult)
+    {
+        return 1;
+    }
+	else if ((*aa).Overallresult > (*bb).Overallresult)
+    {
+        return -1;
+	}
+	else
+    {
+        return 0;
+    }
+}
+
+void sortScore(SS stu[], int N)
+{
+
+	qsort(&(stu[0]), N, sizeof(stu[0]), Ranking);
+
+}
+
+void Putout(SS stu[], int N)
+{
+    int i;
+    cout << "\nStep 3: Output student ranking information based on the total score!\n" << endl;
+    for (i=0;i<N;i++)
+	{
+		printf("The number of the student:%d    number:%s   name:%s Overall result:%4.2f \n",i+1,&(stu[i].number),&(stu[i].name),stu[i].Overallresult);
+	}
+}
+void Meanandstandarddeviation(SS stu[],int N)
+{
+    int i;
+    int project[N];
+    int mean;
+    int cum1=0;
+    int cum2=0;
+    for(i=0;i<N;i++)
+    {
+        cum1=cum1+stu[i].Overallresult;
+    }
+    mean=cum1/N;
+    for(i=0;i<N;i++)
+    {
+        project[i]=(stu[i].Overallresult-mean)*(stu[i].Overallresult-mean);
+        cum2=cum2+project[i];
+    }
+    int sorty=0;
+    sorty=sqrt(cum2)/N;
+    cout << "The average score of these students is:" << mean << endl;
+    cout << "The standard deviation of these students’ grades is:" << sorty << endl;
+}
+void searchfor(SS stu[],int N)
+{
+    int i;
+    char num[20];
+    cout << "Please enter the student number of the student's grade you waqent to find." << endl;
+    cin >> num;
+    for(i=0;i<N;i++)
+    {
+        if(strcmp(stu[i].number,num)==0)
+        {
+            printf("name:%s number:%s   Usual grades:%4.2f  Experimental score:%4.2f    Final grade:%4.2f Overall result:%4.2f \n", (stu[i].name),(stu[i].number), stu[i].Usualgrades, (stu[i].Experimentalscore),stu[i].Finalgrade,stu[i].Overallresult);
+            return;
+        }
+    }
+    cout << "If there is no output, it means the input is wrong!" << endl;
+}