java 该类型的方法 If(boolean) 未定义
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The method If(boolean) is undefined for the type
提问by Minh Hoang
Eclipse keeps giving me the following error:
Eclipse 不断给我以下错误：
Exception in thread "main" java.lang.Error: Unresolved compilation problems:
input cannot be resolved
The method If(boolean) is undefined for the type bai1DinhLuatCuLong
Syntax error, insert ";" to complete Statement
F cannot be resolved to a variable
I do not understand this. What do I need to fix? Why can't I use the If()function?
我不明白。我需要修复什么？为什么我不能使用该If()功能？
I've tried looking through Google and Bing, and I've double checked my Java examples book, but I could not work this out.
我试过浏览谷歌和必应，我已经仔细检查了我的 Java 示例书，但我无法解决这个问题。
import java.util.Scanner;
public class bai1DinhLuatCuLong
{
public static void main(String[] args)
{
System.out.print("Giá trì c?n tìm (F // q // r) : ");
char cantim = input.nextChar();
// HERE THIS IS WHERE I PUT THE IF STATEMENT !!!
If (cantim == 'F') {
Scanner input = new Scanner(System.in);
System.out.print("?? l?n c?a ?i?n tích th? nh?t : ");
double q1 = input.nextDouble();
System.out.print("?? l?n c?a ?i?n tích th? hai : ");
double q2 = input.nextDouble();
System.out.print("Kho?ng cách gi?a 2 ?i?n tích : ");
double r = input.nextDouble();
System.out.print("H? s? k s? t? ??ng ???c ??t là 9*10^9 nh? trong h? SI");
double F = 9 * Math.pow(10,9) * Math.abs(q1) * Math.abs(q2) / Math.pow(r,2);
}
System.out.print("?? l?n l?c t??ng tác gi?a 2 ?i?n tích ?i?m : " + "\n L?u y E là *10");
}
}
回答by assylias
Ifdoes not have a large cap Iin java: it should be if.
IfI在 Java中没有大上限：它应该是if.
回答by kosa
if (cantim == 'F')it should be small i
if (cantim == 'F')它应该很小 i
or
或者
You need to write a method
你需要写一个方法
public boolean If(boolean test)
{
//Your logic.
}
But, based on your code, it seems you are looking for "if"statement than having new method.
但是，根据您的代码，您似乎正在寻找"if"语句而不是新方法。
回答by zie1ony
Maybe You want to do something like this:
也许你想做这样的事情：
Scanner input = new Scanner(System.in);
String cantim = input.next();
if (cantim.equals("F")) {
System.out.println("If F");
} else {
System.out.println("Out of F");
}
