c++,二进制文本读写

[qqqqwwww54321]

while(cin>>t.number>>t.name>>t.phone_number>>t.postal_code>>t.address)
{ stu.write((char*)&t,sizeof(employee)); }
stu.write((char*)&mark,sizeof(employee));
。。。。。
while(stu1&&t.number!=0)
{
cout<<t.number<<" "<<t.name<<" "<<t.phone_number<<" "<<t.postal_code<<" "<<t.address<<endl;
stu1.read((char*)&t,sizeof(employee));
}
这样的读写有问题吗
stu1.read((char*)&t,sizeof(employee))
这个是否会读完一个，里面的会自动移动到下一个数据

[飞天御剑流]

你的代码主要问题在于把employee整个写到文件里去了，这样会连同当前环境对齐产生的空隙也写到文件中去，但代码可能运行于对齐系数不同的环境中，一旦读取文件环境与写入文件环境的对齐状况不同你就完蛋了。把成员分别写入文件才是安全的。

[buyong]

查看stu1的类型，和read函数代码

[qqqqwwww54321]

class employee { public: int number;char name[20];int phone_number;int postal_code;char address[20]; }; const employee mark={ 0,"noname",0,0,"noname"}; int main() { employee t;char s[30],s1[3];ofstream stu;ifstream stu1; stu.open("D:\\employee",ios::out|ios::binary); if(!s){ cout<<"文件打开失败"<<endl;abort();} cout<<"输入编号，姓名，电话号码，邮政编码，地址"<<endl; while(cin>>t.number>>t.name>>t.phone_number>>t.postal_code>>t.address) { stu.write((char*)&t,sizeof(employee)); } stu.write((char*)&mark,sizeof(employee)); stu1.getline(s1,30); stu1.open(s,ios::in|ios::binary); while(stu1&&t.number!=0) { cout<<t.number<<" "<<t.name<<" "<<t.phone_number<<" "<<t.postal_code<<" "<<t.address<<endl; stu1.read((char*)&t,sizeof(t)); } }

[qqqqwwww54321]

不知怎样输不出来

[赵4老师]

推荐使用WinHex软件查看硬盘或文件或内存中的原始字节内容。 不要把 fopen("...","...");fscanf,fprintf,fgets,fgetc,fclose //读时把\r\n替换成\n，写时把\n替换成\r\n;读到\x1a就设置EOF;读写的内容当字符看待 和 fopen("...","...b");fseek,fread,fwrite,fgetc,fclose //不作以上替换，遇到\x1a仍继续读;读写的内容当字节看待 弄混了

#include <stdio.h>
#define field_offset(s,f) (int)(&(((struct s *)(0))->f))
struct AD  { int a; char b[13]; double c;};
#pragma pack(push)
#pragma pack(1)
struct A1  { int a; char b[13]; double c;};
#pragma pack(2)
struct A2  { int a; char b[13]; double c;};
#pragma pack(4)
struct A4  { int a; char b[13]; double c;};
#pragma pack(8)
struct A8  { int a; char b[13]; double c;};
#pragma pack(16)
struct A16 { int a; char b[13]; double c;};
#pragma pack(pop)
int main() {
    printf("AD.a %d\n",field_offset(AD,a));
    printf("AD.b %d\n",field_offset(AD,b));
    printf("AD.c %d\n",field_offset(AD,c));
    printf("\n");
    printf("A1.a %d\n",field_offset(A1,a));
    printf("A1.b %d\n",field_offset(A1,b));
    printf("A1.c %d\n",field_offset(A1,c));
    printf("\n");
    printf("A2.a %d\n",field_offset(A2,a));
    printf("A2.b %d\n",field_offset(A2,b));
    printf("A2.c %d\n",field_offset(A2,c));
    printf("\n");
    printf("A4.a %d\n",field_offset(A4,a));
    printf("A4.b %d\n",field_offset(A4,b));
    printf("A4.c %d\n",field_offset(A4,c));
    printf("\n");
    printf("A8.a %d\n",field_offset(A8,a));
    printf("A8.b %d\n",field_offset(A8,b));
    printf("A8.c %d\n",field_offset(A8,c));
    printf("\n");
    printf("A16.a %d\n",field_offset(A16,a));
    printf("A16.b %d\n",field_offset(A16,b));
    printf("A16.c %d\n",field_offset(A16,c));
    printf("\n");
    return 0;
}
//AD.a 0
//AD.b 4
//AD.c 24
//
//A1.a 0
//A1.b 4
//A1.c 17
//
//A2.a 0
//A2.b 4
//A2.c 18
//
//A4.a 0
//A4.b 4
//A4.c 20
//
//A8.a 0
//A8.b 4
//A8.c 24
//
//A16.a 0
//A16.b 4
//A16.c 24
//
//