stringstream Help...

Hello all-

I need to take the first few lines on standard input and print it out. However, I need to check them against some conditions. I have stored the first line in a string vector and then converted to a string stream in preparation for the second line. The following fails:

Code:

n.clear();
while(getline(cin,n)) {
v.push_back(n);
if(v[0] != "P2"){
exit(1); //Works up to this point
}

stringstream ss(n);
ss >> a;
iv.push_back(n);
if(a < 0)
exit(1);
}

This fails. Some help would be appreciated.

Originally Posted by man exit

void exit(int status);

The exit() function causes normal process termination and the value of status & 0377 is returned to the parent

You sure that's what you want? Your problem would be solved if you found some other way besides exit. Like, returning 0;

Fails how?

Doesn't compile?
Exits when it shouldn't?
Doesn't exit when it should?

What type is a?

What did you actually type in to make it pass/fail?

Post a short and complete example, and the input you type in, if you want a fast and accurate answer.
A few random lines of code without any context just draws a load of questions.

And remember the code tags!

Code:

#include<cstdio>
#include<cstdlib>
#include<vector>
#include<string>
#include<iostream>
#include<sstream>
#include<cmath>
using namespace std;

main() {


int a;
int check;
string n, m, s;
vector <string> v;
vector <int> iv;


n.clear();
while(getline(cin,n)){
    v.push_back(n);
                                                              


vector <string> v;
vector <int> iv;


n.clear();
while(getline(cin,n)){
    v.push_back(n);
    n.clear();
    if(v[0]!= "P2"){
        return 0;
                    }
    //stringstream ss(n);
    //ss >> a;
//  v.push_back(n);
     a = atoi(n.c_str());
    stringstream ss(n);
    ss >> a;
    if (a <0){
        return 0;
    }

}
}

What do you mean by "Second if statement fails" do you mean that it always executes or never executes. Also please notice the third line after your while

Code:

 n.clear();

this clears (erases) anything that was in your variable n so when you get to your stringstream there is nothing in your variable 'n'.

Jim