User input

[Paul McKenzie]

I have console aplication, user is typing command through console and I should do some action according those inputs. One command is on one line only.

for example cp is a command which has 4 parameters, between every 2 parameters can be many whitespaces they doesnt matter, so valid command is e.g.-> cp 4 5 6 9 thats valid.

First, we don't know what state your program is in when you call this function, whether you've already corrupted memory when you call this function, whether "io" is a valid object, etc.

Let's get a full program, and then show us what is the input to make it crash:

#include <vector>
#include <string>
#include <sstream>
#include <fstream>
#include <cctype>
#include <algorithm>
#include <iostream>

using namespace std;

bool has_only_spaces(const std::string &str);

void start(std::istream& in, std::ostream& out)
{
    bool end = true;
    out << ">>>";
    while (end)
    {
        vector<string> tokens;
        string input;
        getline(in,input);    
        if (input.empty())
            input += '\0';

        stringstream ss(input); 
        string buf;

        if (!has_only_spaces(input))
        {
            while (ss >> buf)
                tokens.push_back(buf);
        }
    }
}

bool has_only_spaces(const std::string &str)
{
    return std::count_if(str.begin(), str.end(), isspace) == str.size();
}

int main()
{
    start(cin, cout);
}

That full program is basically your code, except for the has_only_spaces which calls count_if() (no loop required). Take the program above, compile and run it. Tell us if this program crashes, and what input you used to crash the program.

Regards,

Paul McKenzie