I have #include<iomanip> header also and it's still not working.I am getting 2 dec places but it's .00 Why is that?Please help.

here is the code

cout << showpoint << fixed << setprecision (2);

cout<<"The Mean is "<<mean<<endl;

also this code is not working ,when I use the [ ] at the end,I am getting an error so I am using () instead but the calculation is incorrect.Please help

float var=((num[0]-mean)*pow(num[0]-mean,2) + (num[1]-mean)*pow(num[1]-mean,2) + + (num[2]-mean)*pow(num[2]-mean,2))/ (num[arraysize-1]);

#include <iostream>

#include<iomanip>

#include <cmath>

using namespace std;

int main()

{

char choice;

const int arraysize=20;

int num[arraysize];

do

{

cout<<"I will give you the Sum,Mean,Var & the Std Dev of any series of numbers?Y/N:"<<endl;

cin>>choice;

if(choice =='Y'||choice =='y')

{

cout<<"How many numbers will you enter? (up to 20)?"; cin>>num[arraysize];

for (int j=0;j<num[arraysize];j++)

{

cout<<"Enter Number"<<j+1<<":"; cin>> num[j];

}

cout << " You have entered the following:"<<endl;

for (j = 0; j < num[arraysize]; j++)

{

cout << num[j]<<" ";

}

int sum=0;

for (j=0;j<num[arraysize];j++)

sum+= num[j];

cout<<"\nThe Sum is "<<sum<<endl;

float mean= (sum/num[arraysize]);

cout << showpoint << fixed << setprecision (2);

cout<<"The Mean is "<<mean<<endl;

float var=((num[0]-mean)*pow(num[0]-mean,2) + (num[1]-mean)*pow(num[1]-mean,2) + + (num[2]-mean)*pow(num[2]-mean,2))/ (num[arraysize-1]);

cout << showpoint << fixed << setprecision (2);

cout<<"The Varience is " <<var<<endl;

float sqrtvar=sqrt(var);

cout << showpoint << fixed << setprecision (2);

cout<<"The Standard deviation is "<<sqrtvar<<endl;

}

}while(choice!='N'&& choice!='n');

return 0;

}