/**************************************************** Write a program that reads in the file numbers.txt and prints out the standard deviation of the numbers there. The file numbers .txt looks like this: N = 3 DATA: 67 61 82 I.e. there's a header that tells you how many numbers are in the file, and then you get all the numbers. Recall that the standard deviation is ______________________ / -- n / \ (xi - ave)^2 / | ------------ / / n - 1 \/ -- i = 1 ****************************************************/ #include <iostream> #include <fstream> #include <string> using namespace std; int main() { // Open input file, read header, get N = # of int's ifstream IN("numbers.txt"); char c; int N; string s; IN >> c >> c >> N >> s; // Create array A and read N int's from input int *A = new int[N]; for(int i = 0; i < N; i++) IN >> A[i]; // Cycle through array summing all the elements int sum = 0; for(int j = 0; j < N; j++) sum = sum + A[j]; double average = double(sum)/N; // Cycle through the array summing the squares of // the elements minus the average double sqsum = 0; for(int j = 0; j < N; j++) sqsum = sqsum + (A[j]-average)*(A[j]-average); double stddev = sqrt(sqsum/(N-1)); // Print out standard deviation cout << "The standard deviation is " << stddev << endl; return 0; }