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C++/Data types

Question
That is great!
Now I understand why I was getting that output.

So what data type do you suggest I should use to handle numbers of this size 1.7976931348623158e+308?

Imagine you're preparing a prgram that should recognise input like that one, and then carries out some operation on them (e.g. mean, median, etc.). What can I do to make that program recognise the whole number? Is there any special data type that can be extended or made larger to accept specific size?

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Followup To
Question -
Hi Eddie

I created a simple C++ class (I provided below) that would print some mathematical values such as the ‘mean' of some given data or calculating the ‘range', ‘midrange' or ‘median'.

I created a generic version of my class (also provided below), and found double to be a very good type to work with, but then I encountered the following problem:

Using double type, when I enter data: 1.7   1.7, I get the expectable answer which is;
Min. Value = 1.7
Max. Value = 1.7
Range Value = 0
Midrange Value = 1.7
Median Value = 1.7
Mean Value = 1.7
Variance Value  = 0
Std. Deviation = 0

But then the problem starts when I enter larger data like
1.7976931348623158e+308
1.7976931348623158e+308
Min. Value = 1.79769e+308 “Strange! Where is the rest of the number?”
Max. Value = 1.79769e+308
Range Value = 0
Midrange Value = 1.79769e+308
Median Value = 1.79769e+308
Mean Value = Infinity “What does this mean?”
Variance Value  = Infinity
Std. Deviation = Infinity

Can you tell where the problem is? Or how can I fix this so it accepts large values just like the one provided above.

By the way to input the data use the syntax:
<data-number: n1  n2 > (e.g <3: 1.2 2 7 >)
Note the spaces between the numbers and tags.

HOW CAN THIS BE FIXED IS THE MAIN QUESTION!

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <math.h>

using namespace std;

class sample {

vector<double> vec_elements;//data vector of the sample

public:
sample() {}
sample(vector<double> v):vec_elements(v){}

/*Returns the size of the sample.*/
int get_size() const {
return vec_elements.size();
}

/*Sorts the data vector of the sample.*/
void sort_data() {
sort(vec_elements.begin(), vec_elements.end());
}

/*Allowing accessing to values within a vector represented by sample.*/
double & operator[](int index) const {//i.e. now u can use 'smpl[i]'
vec_elements.operator[](index);
}

void push(const double &x) {vec_elements.push_back(x);}

/*Returns the data vector of the sample.*/
const vector<double> &get_data() {
return vec_elements;
}

/*Takes a vector, and copy its contents to the data vector of the sample.*/
void set_data(const vector<double> &v) {
for (int i = 0; i < v.size(); i++) {
vec_elements.push_back(v[i]);
}
}

/*Retrieves the minimum value of the data in the sample.*/
double minimum() {
sort_data();
double minimum_value = vec_elements.front();
return minimum_value;
}

/*Retrieves the maximum value of the data in the sample.*/
double maximum() {
sort_data();
double maximum_value = vec_elements.back();
return maximum_value;
}

/*Retrieves the range of the data in the sample.*/
double range() {
sort_data();
double minimum_value = vec_elements.front();
double maximum_value = vec_elements.back();
return (maximum_value - minimum_value);
}

/*Retrieves the mid range of the data in the sample.*/
double midrange() {
double minimum_value = vec_elements.front();
double maximum_value = vec_elements.back();
double midrange = (maximum_value + minimum_value)/2;
return midrange;
}

/*Sums all the data in the vector.*/
double sum() {
double sum = 0;
for (int i = 0; i < vec_elements.size(); i++) {
sum = sum + vec_elements[i];
}
return sum;
}

/*A method that returns the mean of the data in the sample.*/
double mean() {
double mean = sum()/vec_elements.size();
return mean;
}

/*Squares the numbers.*/
double square(double i) { return i*i; }

/*Calculates the variance of the data sample.*/
double variance() {
double the_mean = mean();
double square_of_subtraction = 0;
double sum_of_square = 0;
double the_variance;
int sample_size = vec_elements.size();

for (int i = 0; i < sample_size; i++) {
square_of_subtraction = square(vec_elements[i] - the_mean);
sum_of_square = sum_of_square + square_of_subtraction;
}
the_variance = sum_of_square/sample_size;
return the_variance;
}

/*Calculates the Standard deviation of the data sample.*/
double std_deviation() {
double deviation = sqrt(variance());
return deviation;
}

/*Calculates the median of the data sample.*/
double median() {
sort_data();//sort the vector first
int sample_size = vec_elements.size();
double median;
double middle_position_one;
double middle_position_two;

if ((sample_size % 2) == 0){//even
middle_position_one = (sample_size /2);
middle_position_two = (sample_size /2)+1;
median = (vec_elements[middle_position_one-1] + vec_elements[middle_position_two-1])/2;
} else
if ((sample_size % 2) != 0) {//odd
middle_position_one = (sample_size /2)+1;
median = vec_elements[middle_position_one-1];

}
return median;
}

};

/*Define the output operator*/
ostream& operator<<(ostream &s, const sample & smpl) {
s << '<' << smpl.get_size() << ':' << ' ';
for (int i = 0; i < smpl.get_size(); i++) {
s << smpl[i] << ' ';
}
s  << '>';
return s;
}

/*Define the operator input.*/
istream& operator>>(istream &s, sample & smpl) {
vector<double> vec;
char left_tag, dots, right_tag;
int size;
double number;
if (s >> left_tag) {
if ((s >> size >> dots) && (left_tag == '<' && dots == ':')) {
int i = 0;
while (i < size) {
s >> number;
vec.push_back(number);
i++;
}
if ((s >> right_tag) && (right_tag == '>')) {
smpl = sample(vec);
cout << "Please ensure the data entered is correct!" << '\n';}
}
return s;
}

------------------------------------

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <math.h>

using namespace std;

/*Generic version of sample class*/
template <typename Item> class samplet {

vector<Item> vec_elements;//data vector of the samplet
typedef vector<double>::iterator iter;

public:
samplet() {}
samplet(vector<Item> v):vec_elements(v){}

/*Returns the size of the samplet.*/
int get_size() const {
return vec_elements.size();
}

/*Sorts the data vector of the samplet.*/
void sort_data() {
iter first_element = vec_elements.begin();
iter last_element = vec_elements.end();
sort(first_element, last_element);
}

/*Allowing accessing to values within a vector represented by samplet.*/
Item & operator[](int index) const {//i.e. now u can use 'smpl[i]'
vec_elements.operator[](index);
}

void push(const Item &x) {vec_elements.push_back(x);}

/*Returns the data vector of the samplet.*/
const vector<Item> &get_data() {
return vec_elements;
}

/*Takes a vector, and copy its contents to the data vector of the samplet.*/
void set_data(const vector<Item> &v) {
for (vector<Item>::const_iterator it  = v.begin(); it != v.end(); ++it) {
vec_elements.push_back(*it);
}
}

/*Retrieves the minimum value of the data in the samplet.*/
Item minimum() {
sort_data();
iter minimum_value = vec_elements.begin();
return *minimum_value;
}

/*Retrieves the maximum value of the data in the samplet.*/
Item maximum() {
sort_data();
iter maximum_value = vec_elements.end()-1;
return *maximum_value;
}

/*Retrieves the range of the data in the samplet.*/
Item range() {
sort_data();
iter minimum_value = vec_elements.begin();
iter maximum_value = vec_elements.end()-1;
return (*maximum_value - *minimum_value);
}

/*Retrieves the mid range of the data in the samplet.*/
Item midrange() {
iter minimum_value = vec_elements.begin();
iter maximum_value = vec_elements.end()-1;
Item midrange = (*maximum_value + *minimum_value)/2;
return midrange;
}

/*Sums all the data in the vector.*/
Item sum() {
Item sum = 0;
for (iter i  = vec_elements.begin(); i != vec_elements.end(); ++i) {
sum = sum + vec_elements[*i];
}
return sum;
}

/*A method that returns the mean of the data in the samplet.*/
Item mean() {
Item mean = sum()/vec_elements.size();
return mean;
}

/*Squares the numbers.*/
Item square(Item i) { return i*i; }

/*Calculates the variance of the data samplet.*/
Item variance() {
Item the_mean = mean();
Item square_of_subtraction = 0;
Item sum_of_square = 0;
Item the_variance;
int samplet_size = vec_elements.size();

for (int i = 0; i < samplet_size; i++) {
square_of_subtraction = square(vec_elements[i] - the_mean);
sum_of_square = sum_of_square + square_of_subtraction;
}
the_variance = sum_of_square/samplet_size;
return the_variance;
}

/*Calculates the Standard deviation of the data samplet.*/
Item std_deviation() {
Item deviation = sqrt(variance());
return deviation;
}

/*Calculates the median of the data samplet.*/
Item median() {
sort_data();//sort the vector first
int samplet_size = vec_elements.size();
Item median;
Item middle_position_one;
Item middle_position_two;

if ((samplet_size % 2) == 0){//even
middle_position_one = (samplet_size /2);
middle_position_two = (samplet_size /2)+1;
median = (vec_elements[middle_position_one-1] + vec_elements[middle_position_two-1])/2;
} else
if ((samplet_size % 2) != 0) {//odd
middle_position_one = (samplet_size /2)+1;
median = vec_elements[middle_position_one-1];

}
return median;
}

};

/*Define the output operator*/
template <typename Item>
ostream& operator<<(ostream &s, const samplet<Item> & smpl) {
s << '<' << smpl.get_size() << ':' << ' ';
for (int i = 0; i < smpl.get_size(); i++) {
s << smpl[i] << ' ';
}
s  << '>';
return s;
}

/*Define the operator input.*/
template <typename Item>
istream& operator>>(istream &s, samplet<Item> & smpl) {
vector<Item> vec;
char left_tag, dots, right_tag;
int size;
Item number;
if (s >> left_tag) {
if ((s >> size >> dots) && (left_tag == '<' && dots == ':')) {
int i = 0;
while (i < size) {
s >> number;
vec.push_back(number);
i++;
}
if ((s >> right_tag) && (right_tag == '>')) {
smpl = samplet<Item>(vec);
cout << "Please ensure the data entered is correct!" << '\n';}
}
return s;
}
------------------------------------

#include <iostream>
#include "sample.h"

using namespace std;

int main (void) {
sample s;
while (cin >> s)
cout << s.minimum() << endl << s.maximum() << endl
<< s.range() << endl << s.midrange() << endl
<< s.median() << endl << s.mean() << endl
<< s.variance() << endl << s.std_deviation() << endl;

return(0);
}

Hello Muzafar Mahgoub, thank you for the question.

I'm reasonably sure that the reason that is happening is because you are overflowing DOUBLE_MAX. The range of a double is 1.7E +/- 308. So you get the first number after the decimal point, and 14 other ones. Although your exponent is correct, you still have multiple numbers after the decimal point, and I believe the compiler is truncating it for you. Please refer to the double data type in the MSDN at msdn.microsoft.com.

On a side note, your code is very clean. It made it a lot easier to sift through it. Most of the code I see is not clean at all.

I hope this information was helpful.

- Eddie

Hello Muzafar Mahgoub, thank you for the question.

Unfortunately, there is no other data type that can store a floating point number that big. The creaters of the language didn't think anyone would ever need that much precision. As for regular numbers, an unsigned long long is the biggest data type I know of.

I hope this information was helpful.

- Eddie

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