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//compile:gcc 011-1.c -o 011-1 -lm

#include <stdio.h>
#include <math.h>
double info(int c1,int c2){

	int i;
	
//int array[5] = {4, 3, 8, 9, 0};	
	double list[2];
	double pr_c1=(double)c1/(c1+c2),pr_c2=(double)c2/(c1+c2),result;
	list[0]=pr_c1,list[1]=pr_c2;

	for (i=0;i<2;i++){
	        result += list[i]*log2(list[i]);
	        //printf("list[i]=%f , result = %f\n",  list[i], result);
	}
	return (-1)*result;
}


int main(void)
{
	double c1=3,c2=5;
	
	printf("entropy:%f\n",info(c1,c2));
	

	return 0;
}