#include"my_math.h"

//入力された数値numberから平均値計算
float math_average(float *number,int max){
    float total=0;
    int count=0;
    do{
	total = total + number[count];
	count++;
    }while(max != count);
    return (float)total/(float)count;
}

//入力数値numberから分散を求める
float math_Decentralization(float *number,int max,float heikin)
{
    float *defl;
    int count;

    defl = (float *)malloc(sizeof(float)*max);
    
    for(count=0;count < max;count++){
	defl[count] = (float)number[count] - heikin;
	defl[count] = defl[count] * defl[count];
    }

    return math_average(defl,max);
    
}

//２つのデータ（number1,number2）の共分散を求める
//maxはnumberの配列数、２つのnumberは同じ配列数でなければらなない。		
float math_Covariance(float *number1,float *number2,int max,float heikin){

    float *defl1,*defl2,total=0;
    int count;
    
    defl1 = (float *)malloc(sizeof(float)*max);
    defl2 = (float *)malloc(sizeof(float)*max);

    for(count=0;count<max;count++){
	defl1[count] = number1[count] - heikin;
	defl2[count] = number2[count] - heikin;
   	total = total + (defl1[count] * defl2[count]);
    }

    return total/max;
}