How can I separate this into 2 functions - c++

Question

I was wondering if anyone could help me with a more elegant way to code this program that I am writing please. The code I have is bellow, I would like to know if there is a way to separate the part that prints out the totals into a new function. I have tried but I always just get the total is 0, so I must be passing things wrong or something.
void printNumbers(int x, double y, double z, double v, int sum, double sum2,int sum3,int sum4){
while(x != 0){
y = sqrt (x);
z = pow (x,2);
v = pow (x,3);
sum = sum + x;
sum2 = sum2 + y;
sum3 = sum3 + z;
sum4 = sum4 + v;
cout << " " << x << setw(12) << setprecision (4) << y << setw(8) << z << setw(8) << v << endl;
x--;
}
cout << " total is" << sum << setw(12) << sum2 << setw(8)<< sum3 << setw(8) << sum4 << endl;
}
This is what I tried, at the time I only had one total to get, but It still did not work just gave the answer 0:
void printFooters(int sum){
cout << " " << "====================================="<< endl;
cout << "Totals " << sum << endl << endl;
cout << " " << "====================================="<< endl;
}
This is how I was calling it in main():
printFooters(sum);

Answer 1

You need to make the sums into references if you want them to be updated.
void printNumbers(int x, double y, double z, double v, int& sum, double& sum2,int& sum3,int& sum4)
If you don't the sums are passed by value, so you just get a copy of the current value of the sums.
Alternatively you can use pointers to the sums, but that would involve changing the syntax when accessing the sum variables.

Answer 2

You should decide first, what variables are input and what variables should carry output. Try to not use one variable for both input and output, it is often more confusing than valuable.
Only input value is x. Everything else is output values. In way you have used that values, content of values is modified only in local copy inside function printNumbers(). They will get lost on end of function. I expect you want to output computed results from function (however then printNumbers is wrong name for that function).
C and C++ always pass variables to function parameters by value. That means, variable is initialized from parameter, but any changes are done only inside function. At the end of function, copy is discarded and will NOT change anything you passed to it.
If you want output from function, you can use return, or use pointers or references to a variable. I suggest to use references in C++, they are easier to understand and easier to use.
Use references instead of copied variables in function. Then, when you modify that value inside function, it will keep modified value after function return.
void f1(int in, int out)
{
out = in + 1;
}
void f2(int in, int &out)
{
out = in + 1;
}
int o1=-1, o2=-1;
f1(1, o1);
f2(1, o2);
cout << o1 << "," << o2 << endl; // will print -1,2
So declare your function as:
void printNumbers(int x, double &y, double &z, double &v, int &sum, double &sum2,int &sum3,int &sum4);
you can then do:
double y,z;
int sum, sum2, sum3, sum4;
printNumbers(4, y, z, sum, sum2, sum3, sum4);
printFooters(sum);
And this time, it should print whatever printNumbers computed. See http://www.cprogramming.com/tutorial/references.html for a bit more, or use google.

Answer 3

You could batch all those parameters into structs, and separate all the calculations and outputs.
This is probably overkill in your case, and is quite a bit of code, but anyway...
struct Powers
{
double sqroot;
int one;
double square;
double cube;
};
Powers calculatePowers(int x)
{
Powers powers;
powers.sqroot = sqrt(x);
powers.one = x;
powers.square = x * x;
powers.cube = x * x * x;
return powers;
}
struct Sums
{
int sum1;
double sum2;
int sum3;
int sum4;
};
Sums addPowers(Sums sums, Powers powers)
{
sums.sum1 += powers.one;
sums.sum2 += powers.sqroot;
sums.sum3 += powers.square;
sums.sum4 += powers.cube;
return sums;
}
void printPowers(Powers powers)
{
cout << " " << powers.one
<< setw(12) << setprecision (4) << powers.sqroot
<< setw(8) << powers.square
<< setw(8) << powers.cube
<< endl;
}
void printTotals(Sums sums)
{
cout << " total is"
<< sums.sum1
<< setw(12) << sums.sum2
<< setw(8) << sums.sum3
<< setw(8) << sums.sum4
<< endl;
}
void doEverything(int x)
{
Sums sums = {0, 0, 0, 0};
while (x > 0)
{
Powers powers = calculatePowers(x);
printPowers(powers);
sums = addPowers(sums, powers);
x--;
}
printTotals(sums);
}