if(number>500)cost = 0.15 else if (number 300)cost =0.10; else if(number 100cost=0.075; else if (number >50)cost =0.057 else cost=0;等价于 if(number> 500) cpst =0.157 else m分号不能丢0.10; else if(number >100) cost = 0.075 else if(number 50) cost =0.05 else cost s 0if(number > 500) cost = 0.15; else if (number > 300) cost = 0.10; else if (number > 100) cost = 0.075; else if (number > 50) cost = 0.05; else cost=0; if (number > 500) cost = 0.15; else if (number > 300) cost = 0.10; else if (number > 100) cost = 0.075; else if (number > 50) cost = 0.05; else cost = 0; 等价于 分号不能丢