如何把循环中的内容逐个相加

[wenfei307]

for($counter=$i; $counter>=1; $counter--){
			$weight="weight_$counter";
			$single_price="single_price_$counter";
			$total_price="$_POST[$weight]"*"$_POST[$single_price]";
			$id="id_$counter";
		}
$big_total_price=$total_price+.......;

大概意思就是把每一次for循环中的$total_price进行相加，最后得出来一个总的$big_total_price，这样的话应该怎么写？

[红KING]

$big_total_price=0; for($counter=$i; $counter>=1; $counter--){ $weight="weight_$counter"; $single_price="single_price_$counter"; $big_total_price+="$_POST[$weight]"*"$_POST[$single_price]"; $id="id_$counter"; }

[ayzen1988]

循环外定义一个变量初始值为0 $total = 0; 循环体内一直加$total_price $total += $total_price;