Convert binary string to float

[bilbo2000]

I am trying to read in a binary file which has the data stored as 32
bit float. I have been trying to figure out how to read this in as 32
bit but everytime I try to read it in the best I can do is a 8 bit
integer.
I was able to do this using a scripting language php, and found that
the data is stored in little endian format, so I would read 4
characters in and reverse the string and declare it a float and the
number would come out correct. I'm not sure exactly how to go about
this in C++ because in some cases I read a char and then print it out
I get '' or null.
This seems like a task that most C++ programmers would run into but I
have not really found any place that covers this.

int main()
{
const int unsigned DATA_SIZE = 401;
const int unsigned FIND_STRING = 99;
char data_array[DATA_SIZE];
char anotherstring[4];
char backstring[4];

std::ifstream data_file("firstdata.dat");

for (i = 0; i < DATA_SIZE - 1; ++i) {
assert(i >= 0);
assert(i < sizeof(data_array)/sizeof(data_array[0]));
data_file >data_array[i];
int newdata = data_array[i];
std::cout << "This is the integer " << newdata << '\n';
}
return(0);
}

[red floyd]

bi*******@comcast.net wrote:

I am trying to read in a binary file which has the data stored as 32
bit float. I have been trying to figure out how to read this in as 32
bit but everytime I try to read it in the best I can do is a 8 bit
integer.
I was able to do this using a scripting language php, and found that
the data is stored in little endian format, so I would read 4
characters in and reverse the string and declare it a float and the
number would come out correct. I'm not sure exactly how to go about
this in C++ because in some cases I read a char and then print it out
I get '' or null.
This seems like a task that most C++ programmers would run into but I
have not really found any place that covers this.

int main()
{
const int unsigned DATA_SIZE = 401;
const int unsigned FIND_STRING = 99;
char data_array[DATA_SIZE];
char anotherstring[4];
char backstring[4];

std::ifstream data_file("firstdata.dat");

for (i = 0; i < DATA_SIZE - 1; ++i) {
assert(i >= 0);
assert(i < sizeof(data_array)/sizeof(data_array[0]));
data_file >data_array[i];

try this:
data_file.read(reinterpret_cast<char *>(&data_array[i]),
sizeof data_array[i]);

int newdata = data_array[i];
std::cout << "This is the integer " << newdata << '\n';
}
return(0);
}

[Diwa]

On Jan 22, 5:26 pm, [e-mail] wrote:

I am trying to read in a binary file which has the data stored as 32
bit float. I have been trying to figure out how to read this in as 32
bit but everytime I try to read it in the best I can do is a 8 bit
integer.
I was able to do this using a scripting language php, and found that
the data is stored in little endian format, so I would read 4
characters in and reverse the string and declare it a float and the
number would come out correct. I'm not sure exactly how to go about
this in C++ because in some cases I read a char and then print it out
I get '' or null.
This seems like a task that most C++ programmers would run into but I
have not really found any place that covers this.

int main()
{
const int unsigned DATA_SIZE = 401;
const int unsigned FIND_STRING = 99;
char data_array[DATA_SIZE];

Shouldn't this be "unsigned char" if you are
reading binary data from stream ?

char anotherstring[4];
char backstring[4];

std::ifstream data_file("firstdata.dat");

for (i = 0; i < DATA_SIZE - 1; ++i) {
assert(i >= 0);
assert(i < sizeof(data_array)/sizeof(data_array[0]));
data_file >data_array[i];
int newdata = data_array[i];
std::cout << "This is the integer " << newdata << '\n';
}
return(0);

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