java实现：计算并输出1-3+5-7+……-99+101的值

public static void main(String[] args) {
		// TODO Auto-generated method stub
		//计算并输出1-3+5-7+……-99+101的值
		int result = 0;
		double dob = 1;
		String str = null;
		for(int i= 1,j=1;i<102;i=i+2,j++){
			//System.out.println(i);
			dob = Math.pow((double)(-1), (double)(j+1));
			
			if(dob>0){
				if(1==j)
					str = String.valueOf((int)dob*i);
				else 
					str = str+"+"+String.valueOf((int)dob*i);
			}else
				str = str+String.valueOf((int)dob*i);
			result = result +(int)dob*i;
			System.out.println(str+"="+result);
			
			
		}