Basic Statistics Again -- with Array and Vector
Overview
Given a list of N floating point numbers, find the mean, maximum, minimum, root-mean-square and standard deviation. Your program will first ask for N, the number of integers in the list, which the user will input. Then the user will input N more numbers. You need to use array and vector to store the numbers and use functions for each calculation.
<< the array implementation is in another page >>
The same problem was addressed with array implementation earlier. If you have not done that, I highly recommend do that one first. In the vector approach, I use a simple main routine to initialize the test vector. Then, it calls two statistics routines.
#include <iostream>
#include <vector>
using namespace std;
double CalculateMax(vector <int>&);
void MinMaxMean(vector <int>&, double&, double&, double&);
int main() {
vector<int> myvector;
myvector.push_back(4);
myvector.push_back(7);
myvector.push_back(3);
cout << CalculateMax(myvector)<< endl;
double small, large, avg;
MinMaxMean(myvector, small, large, avg);
cout << "Min=" << small << "\t Max=" << large << "\t Mean=" << avg << endl;
}
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Implementations of two statistics routines follows:
#include <vector>
using namespace std;
double CalculateMax(vector<int>& data) {
double max = 0;
for (unsigned int i=0; i < data.size(); i++) {
if (data[i] > max) max = data[i];
}
return max;
}
void MinMaxMean(vector<int>& data, double& min, double& max, double& mean) {
double sum=0;
min=INT_MAX;
max=INT_MIN;
if (data.size()==0) { min = max = mean = 0; return; }
for (unsigned int i=0; i<data.size(); i++) {
sum += data[i];
if (data[i] < min) min = data[i];
if (data[i] > max) max = data[i];
}
mean = sum / data.size();
}
Discussions:
The test vector was initialized by program. You can refer to array vs vector example to handle user input.
Compare with array approach, did you notice that we do not worry about the size of the vector?
Parameter passing is an important topic for any programmer. Check out the call by reference subject.