Converting byte value into integer and vice versa

[newstar_water]

Hello,

I need to know how the get the integer value of a byte and vice versa.

I want to get the integer value from a byte read from a binary file.
I also want to convert the integer value back into a byte value for write.

Below I have code where the current byte is read into the variable 'byte". I am basically copying one file to the other.

Thanks.

#include <fstream.h> 
#include <iomanip.h> 
int main() 
{ 
int ind, tot; 
unsigned char byte; 
ifstream infile("inputfile.dat", ios::in | ios::binary); 
ofstream outfile("outputfile.dat", ios::binary ); 

for (!infile) 
{ 
infile.read( byte, 1 ); 
outfile.write( byte, 1 ); 
return 0; 
} 

}

[fzoff]

#include <fstream.h> 
#include <iomanip.h> 
int main() 
{ 
int ind, tot; 
unsigned char byte; 

ifstream infile("inputfile.dat", ios::in | ios::binary); 
ofstream outfile("outputfile.dat", ios::binary ); 

for (!infile) 
{ 
    int iVal;
    unsigned char ucVal;

    infile.read( byte, 1 ); 

    //this code I test with Visual C++.

    //convert unsigned char to integer
    iVal = (int)byte; //int cast 

    //convert integer value to unsigned char
    ucVal = (unsigned char)iVal; //cast to unsigned char 

    outfile.write( byte, 1 ); 

    return 0; 
} 

}

[iadman]

for ex.
string s = "0x31"

i want to convert the string into a byte value...say store in char c.
so i print c...it would display "1".
How to do this?

[dusktreader]

Hello,

I need to know how the get the integer value of a byte and vice versa.

As the first respondent answered in unformatted code, it's as simple as a cast. I would additionally point out that it is useful to understand the type system in c++.

There are several integer types. These include

char
unsigned char
short
unsigned short
int
unsigned int
long
unsigned long

All of these types may be cast between each other directly.