如何在 C++ 中从文件中读取小端整数?
假设我有一个二进制文件；它包含正二进制数，但以 little endian 为 32 位整数
Say I have a binary file; it contains positive binary numbers, but written in little endian as 32-bit integers
如何阅读此文件?我现在有这个.
How do I read this file? I have this right now.
int main() {
FILE * fp;
char buffer[4];
int num = 0;
fp=fopen("file.txt","rb");
while ( fread(&buffer, 1, 4,fp) != 0) {
// I think buffer should be 32 bit integer I read,
// how can I let num equal to 32 bit little endian integer?
}
// Say I just want to get the sum of all these binary little endian integers,
// is there an another way to make read and get sum faster since it's all
// binary, shouldnt it be faster if i just add in binary? not sure..
return 0;
}
推荐答案
这是一种适用于大端或小端架构的方法:
This is one way to do it that works on either big-endian or little-endian architectures:
int main() {
unsigned char bytes[4];
int sum = 0;
FILE *fp=fopen("file.txt","rb");
while ( fread(bytes, 4, 1,fp) != 0) {
sum += bytes[0] | (bytes[1]<<8) | (bytes[2]<<16) | (bytes[3]<<24);
}
return 0;
}
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