Convert binary string to float

[bilbo2000@comcast.net]

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("firs tdata.dat");

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

[red floyd]

Re: Convert binary string to float

bilbo2000@comca st.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("firs tdata.dat");
>
for (i = 0; i < DATA_SIZE - 1; ++i) {
assert(i >= 0);
assert(i < sizeof(data_arr ay)/sizeof(data_arr ay[0]));
data_file >data_array[i];

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

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

[Diwa]

Re: Convert binary string to float



On Jan 22, 5:26 pm, bilbo2...@comca st.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];

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

char anotherstring[4];
char backstring[4];
>
std::ifstream data_file("firs tdata.dat");
>
for (i = 0; i < DATA_SIZE - 1; ++i) {
assert(i >= 0);
assert(i < sizeof(data_arr ay)/sizeof(data_arr ay[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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