#include <stdio.h>

/*
 * 等比数列の和
 * 初項a0=7, 公比d=0.5
 */
int main(void) {
	double a=1, sum=0;	//(初)項、和
	double pre, diff;	//前項、差分
	int i=0;			//i番目
	
	do{
		sum = sum + a;
		pre = a;		//前項
		a = -0.5*a;		//次項
		i = i + 1;
		printf("%d %.8f %.8f",i,pre,a);	//確認用
		if(pre>a){
			diff = pre - a;
		}else{
			diff = a - pre;
		}printf(" %.8f\n",diff);
			
	}while(diff>0.0000001);
	printf("合計 %.7f\n",sum);
	
	return 0;
}