Question

I have several C++ strings with some words. I need to get the first word from every string. Then I have to put all of them into a char array. How can I do it?

Answer 1

Here is one way of doing it…

// SO2913562.cpp 
//


#include <iostream>
#include <sstream>
using namespace std;


void getHeadWords(const char *input[]
                    , unsigned numStrings 
                    , char *outBuf
                    , unsigned outBufSize)
{
    string outStr = "";

    for(unsigned i = 0; i<numStrings; i++)
    {
        stringstream ss(stringstream::in|stringstream::out);
        ss<<input[i];

        string word;
        ss>>word;
        outStr += word;

        if(i < numStrings-1)
            outStr += " ";
    }

    if(outBufSize < outStr.size() + 1)//Accomodate the null terminator.
        //strncpy omits the null terminator if outStr is of the exact same
        //length as outBufSize
        throw out_of_range("Output buffer too small");

    strncpy(outBuf, outStr.c_str(), outBufSize);
}

int main () 
{
    const char *lines[] = {
        "first sentence"
        , "second sentence"
        , "third sentence"
    };

    char outBuf[1024];

    getHeadWords(lines, _countof(lines), outBuf, sizeof(outBuf));

    cout<<outBuf<<endl;

    return 0;
}

But note the above code has marginal error checking and may have security flaws. And needless to say my C++ is a bit rusty. Cheers.