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 ?
blue_gene
you can use sscanf() in C++, but you'll need to #include <cstdio>
Look up a C++ Reference and learn How To Ask Questions The Smart WayOriginally Posted by Bjarne Stroustrup (2000-10-14)
Or you can look up the stringstream class.
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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).you can use sscanf() in C++, but you'll need to #include <cstdio>
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
blue_gene
>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.If you want a one-liner, sscanf is there. Otherwise you're stuck with stringstreams:
Code: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;
My best code is written with the delete key.
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: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"; }
