Why can't I reserve 1,000,000,000 in my vector ?
- by vipersnake005
When I type in the foll. code, I get the output as 1073741823.
#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector <int> v;
cout<<v.max_size();
return 0;
}
However when I try to resize the vector to 1,000,000,000, by v.resize(1000000000); the program stops executing. How can I enable the program to allocate the required memory, when it seems that it should be able to?
I am using MinGW in Windows 7. I have 2 GB RAM. Should it not be possible?
In case it is not possible, can't I declare it as an array of integers and get away? BUt even that doesn't work.
Another thing is that, suppose I would use a file(which can easily handle so much data ).
How can I let it read and write and the same time.
Using fstream file("file.txt', ios::out | ios::in ); doesn't create a file, in the first place. But supposing the file exists, I am unable to use to do reading and writing simultaneously.
WHat I mean is this :
Let the contents of the file be 111111
Then if I run : -
#include <fstream>
#include <iostream>
using namespace std;
int main()
{
fstream file("file.txt",ios:in|ios::out);
char x;
while( file>>x)
{
file<<'0';
}
return 0;
}
Shouldn't the file's contents now be 101010 ? Read one character and then overwrite the next one with 0 ? Or incase the entire contents were read at once into some buffer, should there not be atleast one 0 in the file ? 1111110 ?
But the contents remain unaltered. Please explain.
Thank you.
