C ++动态声明的数组无法正常工作

Question

I am trying to read the file's data into a dynamically declared array, using double *data = new double[14141414]() declaration. Note, it is rather a large file; hence large size of an array.

The problem is I can not put all the data into an array as somewhere around index=14000000 the execution would just stop.
The code compiles just fine (no errors). I did debug and the new returns an address, not 0 or NULL. So looks like there is no problem with memory allocation (ie running out of memory). I even echo-ed the file to screen without array assignment just to see that I am able to read through the file well. All looks good.

Yet, the moment I start putting data into an array, the program would just stop closer to the end but at random locations, Sometime it would be 14000000 sometimes the index would be a little bit more and sometimes a little bit less. There were couple times when the program ran well.

Does anybody know what is going on? I suspect the the computer running out of physical memory and hence this behavior of the program. But if this is so, then why does new operator return an address? Should it return 0 or NULL if memory allocate fails?

Thanks!!

UPDATE: per #Jonathan Potter's request I am including the code here. Thanks!! Really good idea!!

void importData(){

int totalLineCount = 14141414;

double *height = new (nothrow) double[totalLineCount]();
int *weight = new (nothrow) int[totalLineCount]();
double *pulse = new (nothrow) double[totalLineCount]();
string *dateTime = new (nothrow) string[totalLineCount];
int *year = new (nothrow) int[totalLineCount]();
int *month = new (nothrow) int[totalLineCount]();
int *day = new (nothrow) int[totalLineCount]();

fstream dataFile(file.location.c_str(), ios::in);
for (int i = 0; i < totalLineCount; i++) {      
  dataFile >> weight[i] 
      >> height[i] 
      >> pulse[i]
      >> year[i] 
      >> dateTime[i]; 
  } //for
dataFile.close();

delete height;
delete weight;
delete pulse;
delete dateTime;
delete year;
delete month;
delete day;

}//function end

Answer 1

save yourself loads of trouble, use a vector

std::vector<double> data;
data.reserve(SIZE_OF_ARRAY); // not totally required, but will speed up filling the values

vector will give you better debug messages and you won't have to deal with memory yourself.

Answer 2

Your "new" memory allocation block need to correct as follows, there is no need of () at end of each line.

double *height = new (nothrow) double[totalLineCount];
int *weight = new (nothrow) int[totalLineCount];
double *pulse = new (nothrow) double[totalLineCount];
string *dateTime = new (nothrow) string[totalLineCount];
int *year = new (nothrow) int[totalLineCount];
int *month = new (nothrow) int[totalLineCount];
int *day = new (nothrow) int[totalLineCount];

And you "delete" block need to correct as follows:

delete [] height;
delete []weight[];
delete []pulse;
delete []dateTime;
delete []year;
delete []month;
delete []day;

I think improper delete operation may be reason for your failure. You allocated memory for arrays but de-allocated by using pointer syntax of delete instead using array syntax.

And another probability for the issue may be lack of physical memory, because as per code you are allocating a lot of memory, not only a double array as you mentioned earlier in question. There is an array of std::string and a few more.

To avoid all memory allocation and de-allocation hurdles better you can go for std::vector in place of array. In one of your comments you raised concern of performance benefit by comparing array and std::vector. If you are using compiler optimizations , (if in case of gcc -O2 ) std::vector will be at par with array unless you may make some serious mistake in your implementation.