将.txt值推入向量

Question

I've been trying to figure out how to push things from a .txt into a vector and I haven't quite been successful, so I've strayed from my assignment and created a simple code to learn it.

I tried to find a similar post on here but I couldn't, so here's my code:

This is what's in the text file:

32 34 5 6 243 2341 234 213 24 123 12354 124 432 12

This is the code:

#include <iostream>
#include <vector>
#include <fstream>

using namespace std;

int main () {

vector <int> numbers;
int val;
int newval = 50;

  ifstream file ("text.txt");
   if ( file.is_open())
   {
       for ( int i = 0; i < newval ; i++)
       {
            numbers.push_back(val);
       }
   }else{
       cout << "unable to open file."<<endl;
   }

      for ( int i = 0; i < numbers.size(); i++){
        cout << numbers[i] << endl;
      }

 return 0;
}

What the code is doing is printing 50 zeros. I'm not sure what I'm doing wrong, and any insight would be much appreciated! thank you.

P. S - in the initial for loop I was going to do:

for ( int i = 0; i < numbers.size() ; i++)
   {
        numbers.push_back(val);
   }

but that didn't make any sense to me because the vector is initially empty. If that's what I'm supposed to do, please explain. Thanks.

Answer 1

Unless I'm blind, you're never assigning a value to val .

If that is the case, you're getting 0s because that's the default value for int s.

To fix this, you'll need to actually assign a read value to val before adding it to numbers . Also note that it will be read as a string most likely, so you'll have to convert it to an int before it can be assigned to val ; but that's it's own set of problems.

Answer 2

So, After I receiving help from community members here ( carcigenicate and twalberg) I've resolved all problems with the code, and I'm posting it below to help anyone else with this kind of question.

This is the original text file:

32 34 5 6 243 2341 234 213 24 123 12354 124 432 12

Below is the code:

#include <iostream>
#include <vector>
#include <fstream>

using namespace std;

int main () {

vector <int> numbers;
int val=0;


  ifstream file ("text.txt");
   if ( file.is_open())
   {
     while  (! file.eof())
       {
       while (file >> val){
            numbers.push_back(val);
       }
     }
   }else{
       cout << "unable to open file."<<endl;
    }
      for ( int i = 0; i < numbers.size(); i++){
        cout << numbers[i] << endl;
      }

file.close();
 return 0;
}

What prints as output:

32
34
5
6
243
2341
234
213
24
123
12354
124
432
12

Thank you community!