what is the C++ version of this C code ?

hi, i want to extract data from a line.

something like....

char buff[100];
in.getline(buff,100); // in is an inputstream object
if(sscanf(buff,"%d %d",&var1,&var2)==2) // what is the C++
//version of this line ?
cout<<var1<<" "<<var2<<endl;


there are several ways to read data...but i want to know, what is the equivalent code for sscanf() in C++ ? is it possible at all ?

you can use sscanf() in C++, but you'll need to #include <cstdio>

Or you can look up the stringstream class.

Quote:

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you can use sscanf() in C++, but you'll need to #include <cstdio>

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....yes,as C++ is a superset of C. but that will not be pure C++ programming....it will be mixed thing(although no error).


actually, i was thinking a C code

fgets(buff,100,ptr) // it is similar to getline() in C++
sscanf( buff,"%d %d",&var1,&var2) // what is similar in C++?

in fact in this case i was expecting similar C++ function if exist .

thanks

>but that will not be pure C++ programming....
Yes it will. If the C++ standard defines a construct, then it's "pure" C++. fgets and sscanf just don't conform to your idea of "pure" C++.

>it will be mixed thing(although no error).
And what's wrong with that? It seems to me that you're needlessly restricting yourself with this skewed concept of "pure" C++.

>in fact in this case i was expecting similar C++ function if exist
Pure C++ doesn't use archaic things like functions, it uses objects. :rolleyes: If you want a one-liner, sscanf is there. Otherwise you're stuck with stringstreams:

Code:

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string buff;
int var1, var2;
//fgets(buff,100,ptr) // it is similar to getline() in C++
getline ( cin, buff );
//sscanf( buff,"%d %d",&var1,&var2) // what is similar in C++?
istringstream cppsscanf ( buff );
cppsscanf>> var1 >> var2;

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Just to clarify a bit, the equivilant of sscanf(...) == 2 is to evaluate the istringstream in a boolean context, or test !fail(). Here is preludes code with a bit more error checking.

Code:

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std::string buff;
if(std::getline(std::cin, buff)) {
    std::istringstream iss(buff);
    int a,b;
    if(iss >> a >> b) {
        std::cout << a << ", " << b << std::endl;
    } else {
        std::cerr << '"' << iss.str() << "\" does not start with two ints\n";
        iss.clear(); // clear all errors
        char ch;
        if(iss.get(ch)) {
            std::cerr << "confused by '" << ch << "' at pos "
                      << static_cast<int>(iss.tellg())-1 << std::endl;
        } else if(iss.eof()) {
            std::cerr << "unexpected end of file\n";
        } else { // in theory we never reach here
            std::cerr << "unrecoverable internal stream error\n";
        }
    }
} else {
    std::cerr << "Could not read from standard input\n";
}

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