請(qǐng)問(wèn)各位哪錯(cuò)了
public?class?math{ public?static?void?main(String[]?args){ double?end=2*(x*x)+3*x; int?x=2; System.out.println("計(jì)算的結(jié)果:"+end); } }
public?class?math{ public?static?void?main(String[]?args){ double?end=2*(x*x)+3*x; int?x=2; System.out.println("計(jì)算的結(jié)果:"+end); } }
2016-11-28
舉報(bào)
2016-11-28
public?class?math{
????public?static?void?main(String[]?args){
? ? ? ? int?x=2; //必須先聲明在使用
????????double?end=2*(x*x)+3*x;
? ? ? ? System.out.println("計(jì)算的結(jié)果:"+end);
????}
}
2017-01-16
變量先聲明再使用
2016-12-10
x變量由于之前沒(méi)有聲明,所以在用x對(duì)end賦值時(shí)無(wú)法識(shí)別x