parse/split a string and store it in variables

hey im trying to make a program and i need to parse/split a line of code and store it in string variables ex: scan documents\download ---> command=scan; arg=documents download, now i saw another thread similar but when i tried to impliment everything into variable, the program crashes, comment it out, runs perfectly, any ideas?

Never assume code you find somewhere is correct. Try to understand what is there. Other than that its the same old routine. Hard enough to read tea leaves in the cup before me, let alone over the phone.

I wrote a tutorial on tokenizing in our faq

Boost also has a StringTokenizer template.

yes i understand why the code works. the code works on its own, however when i attempt to modify it to put it in a variable instead of printing it out but it gives me a system crash, i put in spot checks and i found out the code chrashes as soon as it hits the point where im assigning the values to the variables, here is what it looks like:

#include <iostream>
#include <vector>
#include <string>
#include <conio.h>

void Prompt()
{
std::string s;
std::cin>>s;
std::string command;
std::string arg;
std::cout<<"PROMPT1";
std::vector<std::string> vec;
std::cout<<"PROMPT2";
int start = 0, end = 0;
std::cout<<"PROMPT3";
while ( end != std::string::npos ) {
end = s.find ( ' ', start );
std::cout<<"PROMPT4";
vec.push_back ( s.substr ( start, end - start ) );
std::cout<<"PROMPT5";
start = end + 1;
}

std::cout<<"PROMPT6";
command = vec[0];
arg = vec[1];
std::cout<<"PROMPT7";
std::cout<<command<<arg;

if(command=="cls")
{
//clrscr();
}
else
{
std::cout<<"ERROR";
}
}

int main()
{
Prompt();
}

code tags...

put [code] ... [/code] around your source code, so it's readable.

Code:

---

#include <iostream>
#include <vector>
#include <string>
#include <conio.h>

void Prompt()
{
std::string s;
        std::cin>>s;
std::string command;
std::string arg;
                                                            std::cout<<"PROMPT1";
  std::vector<std::string> vec;
                                                          std::cout<<"PROMPT2";
  int start = 0, end = 0;
                                                          std::cout<<"PROMPT3";
  while ( end != std::string::npos )
 {
    end = s.find ( ' ', start );
                                                          std::cout<<"PROMPT4";
    vec.push_back ( s.substr ( start, end - start ) );
                                                          std::cout<<"PROMPT5";
    start = end + 1;
  }

                                                          std::cout<<"PROMPT6";
command = vec[0];
arg = vec[1];
                                                          std::cout<<"PROMPT7";
        std::cout<<command<<arg;

if(command=="cls")
        {
        //clrscr();
        }
else
        {
        std::cout<<"ERROR";
        }
}

int main()
{
Prompt();
}

---

sorry i forgot and since im guest i cant edit

[B]

Code:

---

#include <iostream>
#include <vector>
#include <string>
#include <conio.h>

void Prompt()
{
std::string s;
//std::cin>>s;
getline(cin, s); // change here
std::string command;
std::string arg;
                                                            std::cout<<"PROMPT1";
  std::vector<std::string> vec;
                                                          std::cout<<"PROMPT2";
  int start = 0, end = 0;
                                                          std::cout<<"PROMPT3";
  while ( end != std::string::npos )
 {
    end = s.find ( ' ', start );
                                                          std::cout<<"PROMPT4";
    vec.push_back ( s.substr ( start, end - start ) );
                                                          std::cout<<"PROMPT5";
    start = end + 1;
  }

                                                          std::cout<<"PROMPT6";
command = vec[0];
arg = vec[1];
                                                          std::cout<<"PROMPT7";
        std::cout<<command<<arg;

if(command=="cls")
        {
        //clrscr();
        }
else
        {
        std::cout<<"ERROR";
        }
}

int main()
{
Prompt();
}

---

I made one change at the start of your code, try it now :)

ok thx laasunde it now works, so i got the main part down, now how do you evaluate the string? i believe i use:

Code:

---

if(command=="cls")
        {
        clrscr();
        }
else
        {
        std::cout<<"ERROR";
        }

---

but when i compile i get the error when i enter cls home, it gives me the error instead of the clrscreen. any ideas on that?

Quote:

---

Originally posted by StRiKeFoRcEnOoB
ok thx laasunde it now works, so i got the main part down, now how do you evaluate the string? i believe i use:

Code:

---

if(command=="cls")
        {
        clrscr();
        }
else
        {
        std::cout<<"ERROR";
        }

---

but when i compile i get the error when i enter cls home, it gives me the error instead of the clrscreen. any ideas on that?

---

Are you typing cls with lowercase ?

You should check out Faq : Clear the screen.

Code:

---

if(command==string("cls"))
        {
        clrscr();
        }
else
        {
        std::cout<<"ERROR";
        }

---

this works now i need to know this real quick. i got this

Code:

---

command = vec[0];
arg = vec[1];

---

but i get an error if there is nothing stored in vec[1], how can i make an if-else evalutaion to fulfill this pseudocode

Code:

---

    if(vec[1]=true] //meaning something is present
      { string arg=vec[1];}
    else
      { string arg;}

---

i recall see how to do it before but i can not find my reference guide, so if you can help that would be appreciated

Code:

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  if (vec.size() > 1)
  {
    // if true, you have more than one parameter...
  }

---