Thread: Reading from a .txt file or use arrays.

If you keep reading the file until the value becomes null, it is possible. You just have to keep looping with the condition that the value == NULL, to stop the reading.

With the code provided in your post, you can do what you have done without the fstream. Here let me revise it for you.

Code:

#include <iostream.h> 
#include <stdio.h> 

/*void*/ int main() //do not use void.  Read the FAQ on why
{ 
     int Amt; //total numbers to loop
     int i=0;  //starting point
     char str[50]; //an array

     { 
          cout<<"Welcome to the math program.\n"; 
          cout<<"How may numbers do you want to use?"; 
          cin>>Amt; //user input for loop count
     } 

     while(i<Amt) 
     { 
          i++; 
          cout<<"adding 1 to "<<i<<endl;
     } 
}

You can use the new and delete keywords to allocate arrays dynamically:

PHP Code:

#include <iostream.h> 

int main()
{

    int* variables = NULL; 
    int  count;
    int  i;
    int  sum;

    do
    {
        cout << "How many variables would you like to enter ? ( 1+ )";
        cin >> count;
    }
    while( count <= 0 );

    // now count is a positive number

    variables = new int[count];

    if( variables == NULL )
    {
        cerr << "Error, not enough RAM" << endl;
        return 1;
    }

    // read variables into array
    for( i = 0 ; i < count ; i++ )
    {
        cout << "Enter variable #" << i+1 << ":";
        cin >> variables[i];
    }

    sum = 0;

    // add them all 
    for( i = 0 ; i < count ; i++ )
    {
        if( i != 0 ) cout << "+";

        cout << variables[i];

        sum = sum + variables[i];
    }

    cout << " = " << sum << endl;
    
    if( variables != NULL ) delete [] variables;

    return 0;
}