阐述 C 语言中用于文件操作的 fread() 和 fwrite() 函数
问题
编写一个 C 语言程序,用文件保存 5 个学生的详细信息,然后再使用 fread() 和 fwrite() 打印这些信息
解决方案
fread() 函数每次读取整个记录。
语法
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() 函数每次写入整个记录。
语法
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);
程序
#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( ); }
输出
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
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