How to read and write float numbers from and into binary files? [duplicate]

Answer 1

fwrite() and fread() or write() and read() will work just fine.

float da, db ;
    ...
fwrite( &da, 1, sizeof(da), fpout ) ;
    ...
fread( &db, 1, sizeof(db), fpin ) ;

Answer 2

In Vala you can do:

public void main() {
    float foutvalue = 5.55;
    { //Need to make vala close the output file!
        var output = FileStream.open("floatfile","w");
        output.printf("%f", foutvalue);
    }

    float finvalue = 0.0;
    {
        var input = FileStream.open("floatfile", "r");
        input.scanf("%f", out finvalue);
    }
    print(@"$finvalue\n");
}