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#include "stdio.h"
#include"string.h"
#include"stdlib.h"
struct Student
{
char ID[20];
char Name[20];
float Mark1;
float Mark2;
float Mark3;
float Average;
};
struct Student students[1000];
int num=0;
float Avg(struct Student stu)
{
return (stu.Mark1+stu.Mark2+stu.Mark3)/3;
}
int Student_SearchByIndex(char id[])
{
int i;
for (i=0;i<num;i++)
{
if (strcmp(students[i].ID,id)==0)
{
return i;
}
}
return -1;
}
/*Returns the array subscript by Name*/
int Student_SearchByName(char Name[])
{
int i;
for (i=0;i<num;i++)
{
if (strcmp(students[i].Name,Name)==0)
{
return i;
}
}
return -1;
}
/*Display a single student record*/ Student number
void Student_DisplaySingle(int index)
{
printf("%10s%10s%8s%8s%8s%10s\n","Student number","Name","Higher Mathematics score","C Language score","Computers score","Average score");
printf("-------------------------------------------------------------\n");
printf("%10s%10s%8.2f%8.2f%8.2f%10.2f\n",students[index].ID,students[index].Name,students[index].Mark1,students[index].Mark2,students[index].Mark3,students[index].Average);
}
/*Insert student information*/
void Student_Insert()
{
while(1)
{
printf("Please enter Student number:");
scanf("%s",&students[num].ID);
getchar();
printf("Please enter Name:");
scanf("%s",&students[num].Name);
getchar();
printf("Please enter Higher Mathematics score:");
scanf("%f",&students[num].Mark1);
getchar();
printf("Please enter C Language score:");
scanf("%f",&students[num].Mark2);
getchar();
printf("Please enter Computers score:");
scanf("%f",&students[num].Mark3);
getchar();
students[num].Average=Avg(students[num]);
num++;
printf("Whether to continue?(y/n)");
if (getchar()=='n')
{
break;
}
}
}
/*Modify student information*/
void Student_Modify()
{
//float mark1,mark2,mark3;
while(1)
{
char id[20];
int index;
printf("Please enter the student to be modified's Student number:");
scanf("%s",&id);
getchar();
index=Student_SearchByIndex(id);
if (index==-1)
{
printf("Students do not exist!\n");
}
else
{
printf("The student information you want to modify is:\n");
Student_DisplaySingle(index);
printf("-- Please enter a new value--\n");
printf("Please enter Student number:");
scanf("%s",&students[index].ID);
getchar();
printf("Please enter Name:");
scanf("%s",&students[index].Name);
getchar();
printf("Please enter Higher Mathematics score:");
scanf("%f",&students[index].Mark1);
getchar();
printf("Please enter C Language score:");
scanf("%f",&students[index].Mark2);
getchar();
printf("Please enter Computers score:");
scanf("%f",&students[index].Mark3);
getchar();
students[index].Average=Avg(students[index]);
}
printf("Whether to continue?(y/n)");
if (getchar()=='n')
{
break;
}
}
}
/*Delete Student Information*/
void Student_Delete()
{
int i;
while(1)
{
char id[20];
int index;
printf("Please enter the student to be deleted's Student number:");
scanf("%s",&id);
getchar();
index=Student_SearchByIndex(id);
if (index==-1)
{
printf("Students do not exist!\n");
}
else
{
printf("The student information you want to delete is:\n");
Student_DisplaySingle(index);
printf("Is it really necessary to delete?(y/n)");
if (getchar()=='y')
{
for (i=index;i<num-1;i++)
{
students[i]=students[i+1];//Move all the objects behind you forward
}
num--;
}
getchar();
}
printf("Whether to continue?(y/n)");
if (getchar()=='n')
{
break;
}
}
}
/*Search by Name*/
void Student_Select()
{
while(1)
{
char Name[20];
int index;
printf("Please enter the student's Name:");
scanf("%s",&Name);
getchar();
index=Student_SearchByName(Name);
if (index==-1)
{
printf("Students do not exist!\n");
}
else
{
printf("The student information you are looking for is:\n");
Student_DisplaySingle(index);
}
printf("Whether to continue?(y/n)");
if (getchar()=='n')
{
break;
}
}
}
/*Sort by average*/
void Student_SortByAverage()
{
int i,j;
struct Student tmp;
for (i=0;i<num;i++)
{
for (j=1;j<num-i;j++)
{
if (students[j-1].Average<students[j].Average)
{
tmp=students[j-1];
students[j-1]=students[j];
students[j]=tmp;
}
}
}
}
/*Show student information*/
void Student_Display()
{
int i;
printf("%10s%10s%8s%8s%8s%10s\n","Student number","Name","Higher Mathematics score","C Language score","Computers score","Average score");
printf("-------------------------------------------------------------\n");
for (i=0;i<num;i++)
{
printf("%10s%10s%8.2f%8.2f%8.2f%10.2f\n",students[i].ID,students[i].Name,students[i].Mark1,students[i].Mark2,students[i].Mark3,students[i].Average);
}
}
/*Read student information out of the file*/
void IO_ReadInfo()
{
FILE *fp;
int i;
if ((fp=fopen("Database.txt","rb"))==NULL)
{
printf("Cannot open file!\n");
return;
}
if (fread(&num,sizeof(int),1,fp)!=1)
{
num=-1;
}
else
{
for(i=0;i<num;i++)
{
fread(&students[i],sizeof(struct Student),1,fp);
}
}
fclose(fp);
}
/*Writing student information to a file*/
void IO_WriteInfo()
{
FILE *fp;
int i;
if ((fp=fopen("Database.txt","wb"))==NULL)
{
printf("Cannot open file!\n");
return;
}
if (fwrite(&num,sizeof(int),1,fp)!=1)
{
printf("Write to file error!\n");
}
for (i=0;i<num;i++)
{
if (fwrite(&students[i],sizeof(struct Student),1,fp)!=1)
{
printf("Write to file error!\n");
}
}
fclose(fp);
}
/*Main Program*/
void main()
{
int choice;
IO_ReadInfo();
while(1)
{
/*Main Menu*/
printf("\n------ Student Management System------\n");
printf("1. Adding student records\n");
printf("2. Modify student records\n");
printf("3. Delete student records\n");
printf("4. Search Student Records by Name\n");
printf("5. Sorted by average score\n");
printf("6. Exit\n");
printf("Please select(1-6):");
scanf("%d",&choice);
getchar();
switch(choice)
{
case 1:
Student_Insert();
break;
case 2:
Student_Modify();
break;
case 3:
Student_Delete();
break;
case 4:
Student_Select();
break;
case 5:
Student_SortByAverage();
Student_Display();
break;
case 6:
exit(0);
break;
}
IO_WriteInfo();
}
}
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