私は与えられたデータを使ってカイ二乗値を計算するプログラムを書いた。しかし、私のプログラムは、それが読み込んでいるテキストファイルにいくつの行があるのか分からないように記述する必要があります。構造点をポイント[1000](つまり、ファイル内の行数よりも大きい)として定義すると、計算が機能せず、最終的に 'ナノ'値になります。私は、入力ファイルを添付している読み込み中のデータテキストファイルにいくつの行が含まれているかを事前に知らないために、C++でプログラムを書く方法を教えてください。
#include<iostream>
#include<fstream>
#include<cmath>
using namespace std;
//define my own data structure
struct point {
double x;
double y;
double s;
double w;
double wx;
double wy;
double wxy;
double wxx;
double wmxcy;
};
//main program
int main() {
//array of point
point thePoints[11];
int i = 0;
//open a file to read in
ifstream myFile ("xys.data.txt");
//check if it opened successfully
if (myFile.is_open()) {
//file is open
//read it in
while (!myFile.eof()) {
//whilst we are not at the end of the file
myFile >> thePoints[i].x >> thePoints[i].y >> thePoints[i].s;
//increment i
i++;
}
//close the file
myFile.close();
}
// something went wrong
else {
cout << "Error opening file!\n";
exit(1);
}
// data is now in an array of point structures
//set the summation variables to zero - sets an initial value for the rest of the appropriate array to then be added onto
double Sw = 0;
double Swxx = 0;
double Swxy = 0;
double Swx = 0;
double Swy = 0;
double xsq = 0;
//create an array for w
for (int j = 0; j <= 10; j++){
thePoints[j].w = 1/(pow((thePoints[j].s),2));
//sum over all w i.e. create an array for Sw
Sw += thePoints[j].w;
//create an array for wx
thePoints[j].wx = (thePoints[j].w) * (thePoints[j].x);
//sum over all wx i.e. create an array for Swx
Swx += thePoints[j].wx;
//create an array for wy
thePoints[j].wy = (thePoints[j].w) * (thePoints[j].y);
//sum over all wy i.e. create an array for Swy
Swy += thePoints[j].wy;
//create an array for wxy
thePoints[j].wxy = (thePoints[j].w) * (thePoints[j].x) * (thePoints[j].y);
//sum over all wxy i.e. create an array for Swxy
Swxy += thePoints[j].wxy;
//create an array for wxx
thePoints[j].wxx = (thePoints[j].w) * (thePoints[j].x) * (thePoints[j].x);
//sum over all wxx i.e. create an array for Swxx
Swxx += thePoints[j].wxx;
}
printf("%6.2f, %6.2f, %6.2f, %6.2f, %6.2f\n", Sw, Swx, Swy, Swxy, Swxx);
//caluculate a value for D
double D = ((Sw * Swxx) - (Swx * Swx));
//calculate a value for m
double m = ((Sw * Swxy) - (Swx * Swy))/D;
//calculate a value for dm
double dm = sqrt(Sw/D);
//calculate a value for c
double c = ((Swy * Swxx) - (Swx * Swxy))/D;
//calculate a value for dc
double dc = sqrt(Swxx/D);
//calculate chi-squared value, xsq = Sw(((m * x) + c - y)^2)
for (int j = 0; j < i; j++){
thePoints[j].wmxcy = (thePoints[j].w * (pow(((m * thePoints[j].x) + c - thePoints[j].y),2)));
//sum over all chi-squared
xsq += thePoints[j].wmxcy;
}
//prints all of the results of the data
printf("The equation of the line for the data is y = %6.2f x + %6.2f.\n", m, c);
printf("The gradient, m, has an associated error of %6.2f.\n", dm);
printf("The y intercept, c, has an associated error of %6.2f.\n", dc);
printf("The data has a chi-squared value of %6.2f.\n", xsq);
return 0;
}
: はここに私のプログラムです。 txt file
ご意見は大歓迎です。
http://en.cppreference.com/w/cpp/numeric/math/nan、https://en.m .wikipedia.org/wiki/NaN –
[なぜ 'while(myFile.eof())'が間違っているのですか?](https://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition -considered-wrong) – Barmar
問題を再現するサンプル入力データなしで問題を特定するのは難しいかもしれません。 –