我最近进行了编程测试，其中有一个ifstream部分无法解决。从那时起，我一直试图在空闲时间解决问题，但无济于事。
问题基本上是从二进制文件读取并在其中提取信息。
这是文件格式:
------------------------------------------------------------------------------ | File Offset (in Bytes)| Value Type | Value Description | ------------------------------------------------------------------------------ | 0 | Unsigned Integer (32 bits) | number of entities | ------------------------------------------------------------------------------ | 4 | Entity information (see | Entity 0 | | | below) | | ------------------------------------------------------------------------------ | 4+32 | Entity Information | Entity 1 | ------------------------------------------------------------------------------ | ... | ... | ... | ------------------------------------------------------------------------------ | 4 + (32 * N) | Entity Information | Entity N | ------------------------------------------------------------------------------ Entity Information: ------------------------------------------------------------------------------ | Offsett (in Bytes)| Value Type | Value Description | ------------------------------------------------------------------------------ | 0 | Unsigned short (16 bits) | Unique ID | ------------------------------------------------------------------------------ | 2 | Unsigned short (16 bits) | Entity type ID | ------------------------------------------------------------------------------ | 4 | Single-precision float (32 | Position X coordinate | | | bits) | | ------------------------------------------------------------------------------ | 8 | Single-precision float (32 | Position Y coordinate | | | bits) | | ------------------------------------------------------------------------------ | 12 | Single-precision float (32 | Forward Normal X | | | bits) | Component | ------------------------------------------------------------------------------ | 16 | Single-precision float (32 | Forward Normal Y | | | bits) | Component | ------------------------------------------------------------------------------
And here is my code:
void readFile()
{
ifstream ifs ( "binaryFile.bin" , ifstream::in );
while (ifs.good())
{
int numEntities = 0;
ifs.read( (char*)&(numEntities), sizeof(unsigned short));
for(int i=0; i<numEntities; i++)
{
unsigned short uID;
unsigned short eID;
float x;
float y;
float forward_x;
float forward_y;
ifs.read( (char*)&(uID), sizeof(unsigned short) );
ifs.read( (char*)&(eID), sizeof(unsigned short) );
ifs.read( (char*)&(x), sizeof(float) );
ifs.read( (char*)&(y), sizeof(float) );
ifs.read( (char*)&(forward_x), sizeof(float) );
ifs.read( (char*)&(forward_y), sizeof(float) );
}
}
ifs.close();
}
谢谢。
最佳答案
当您说自己有问题时，您会看到什么输出，它与您希望看到的输出有何不同？
一些一般性建议:一方面，如果要读取二进制数据，请尝试以二进制模式open读取流。
同样，您的第一个read操作将数据存储到int中，但是读取的长度为unsigned short。这是故意的吗？
当您将指针转换为char*的第一个参数read时，请尝试使用显式的reinterpret_cast<char *>。