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Legal Studies闡述 C 語言中用於檔案操作的 fread() 和 fwrite() 函式
問題
編寫一個 C 語言程式，用檔案儲存 5 個學生的詳細資訊，然後再使用 fread() 和 fwrite() 列印這些資訊
解決方案
fread() 函式每次讀取整個記錄。
語法
fread( & structure variable, size of (structure variable), no of records, file pointer);
示例
struct emp{
int eno;
char ename [30];
float sal;
} e;
FILE *fp;
fread (&e, sizeof (e), 1, fp);fwrite() 函式每次寫入整個記錄。
語法
fwrite( & structure variable , size of structure variable, no of records, file pointer);
示例
struct emp{
int eno:
char ename [30];
float sal;
} e;
FILE *fp;
fwrite (&e, sizeof(e), 1, fp);程式
#include<stdio.h>
struct student{
int sno;
char sname [30];
float marks;
char temp;
};
main ( ){
struct student s[60];
int i;
FILE *fp;
fp = fopen ("student1.txt", "w");
for (i=0; i<2; i++){
printf ("enter details of student %d
", i+1);
printf("student number:");
scanf("%d",&s[i].sno);
scanf("%c",&s[i].temp);
printf("student name:");
gets(s[i].sname);
printf("student marks:");
scanf("%f",&s[i].marks);
fwrite(&s[i], sizeof(s[i]),1,fp);
}
fclose (fp);
fp = fopen ("student1.txt", "r");
for (i=0; i<2; i++){
printf ("details of student %d are
", i+1);
fread (&s[i], sizeof (s[i]) ,1,fp);
printf("student number = %d
", s[i]. sno);
printf("student name = %s
", s[i]. sname);
printf("marks = %f
", s[i]. marks);
}
fclose(fp);
getch( );
}輸出
enter details of student 1 student number:1 student name:pinky student marks:56 enter details of student 2 student number:2 student name:rosy student marks:87 details of student 1 are student number = 1 student name = pinky marks = 56.000000 details of student 2 are student number = 2 student name = rosy marks = 87.000000
更新日期：2021 年 3 月 6 日
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