ZMQ / random generator

ELIF

I use ZMQ in QT .In server code :

 srand (time(NULL));
while (1) {
    char buffer [100];
    for(int i=0; i<100; i++){
        buffer[i]=rand()%1000;
    }
zmq_recv (responder, buffer, 100, 0);

 In client code QT:

      ```
    zmq_recv (requester, buffer, 100, 0);
    for(int i=0; i<100; i++){
    printf("%c : ",buffer[i]);
    qDebug() << "buffer[" << i << "] : " << buffer[i];
    }
               ```

But I get negative values also.I want to get values between 0-1000 .What is the problem?
My output is

...
buffer[ 44 ] :  -1476324256
buffer[ 45 ] :  127
buffer[ 46 ] :  0
buffer[ 47 ] :  0
buffer[ 48 ] :  0
buffer[ 49 ] :  0
buffer[ 50 ] :  0
buffer[ 51 ] :  0
buffer[ 52 ] :  -1717986918
buffer[ 53 ] :  1069128089
buffer[ 54 ] :  -1301787792
buffer[ 55 ] :  85
buffer[ 56 ] :  0
buffer[ 57 ] :  0
buffer[ 58 ] :  -1288257088
buffer[ 59 ] :  127
buffer[ 60 ] :  0
buffer[ 61 ] :  0
buffer[ 62 ] :  0
buffer[ 63 ] :  0
buffer[ 64 ] :  0
buffer[ 65 ] :  1072693248
....

JonB

@ELIF said in ZMQ / random generator:

But I get negative values also.I want to get values between 0-1000 .What is the problem?

You store your random numbers in a char. That is signed, hence negative values (where value > 127). How do you intend numbers up to 1000 to fit into a char, I'd love to know?

J.Hilk

you can do a simple linear projection

something like this:

template<typename typeIn, typename typeOut>
typeOut mapToRange(typeIn value,
                    typeIn inMax = std::numeric_limits<typeIn>::max(),
                    typeIn inMin = std::numeric_limits<typeIn>::min(),
                    typeOut outMax = std::numeric_limits<typeOut>::max(),
                    typeOut outMin = std::numeric_limits<typeOut>::min() ){
    //Mapping follows: Y = (X-minRangeOld)/(maxRangeOld-minRangeOld) * (maxRangeNew-minRangeNew) + minRangeNew
    auto mapped = static_cast<double>(value - inMin) / (inMax - inMin) * (outMax - outMin) +  outMin;

    return static_cast<typeOut>(mapped);
}

ELIF

This post is deleted!

SGaist

Hi,

Since you are using ZMQ, you should build a proper message to transmit your data.

Don't send your int values as char. You need to convert the values into their "string" representation. Essentially your table should be ["0", "420", "12", ...].