printf("稅額:\t%.2f\n",(salary*tax)); 稅額: 51840.00 printf("稅額:\t%.3f\n",(salary*tax)); 稅額: 51839.999 讓printf去幫你作四捨五入如何? -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.123.102.254