从文件中读取结构体变量的数据读取和写入结构体数据到文件

#include <stdio.h>

size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);


size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);

struct A
{
int a;
int b;
char c;
double d;
};
void freadtest()
{
struct A tmp,test;
tmp.a =1;
tmp.b= 2;
tmp.c = 'a';
tmp.d = 1.235;

FILE *fd = fopen("a1.txt","a+");
if(fd == NULL)
cout<<"open fail"<<endl;
cout<<fread(&test,sizeof(tmp),1,fd)<<endl;
cout<<fwrite(&tmp,sizeof(tmp),1,fd)<<endl;
cout<<test.c<<endl;
fclose(fd);
cout<<getlogin()<<endl;
}
int main()
{
cout<<"=====fread_fwriteTest======"<<endl;
freadtest();
return 1;
}