java同一个类中两个函数之间的变量值怎么不一样了

写的一个输入二进制，输出十进制的程序
void getInput() {
Scanner in = new Scanner(System.in);
System.out.print("Input a binary number: ");
int [color=red]inpNum[/color] = in.nextInt();
inpBin = String.valueOf(inpNum);

}

void testInput() {

    if ([color=red]inpNum[/color] < NO3) {              /* value must in the scope of int */
        if ([color=red]inpNum[/color] < NO0) {          /* value must bigger than 0 */
            System.out.println("Input must be >=0" + "\n");
            process();
        } else if ([color=red]inpNum[/color] == NO0) {  /* if value equals 0 */
            System.out.println("0");
            System.out.println("Base 2 Equals");
            System.out.println("0");
            System.out.println("Base 10");
        } else {                        
            for (int i=NO0; i<inpBin.length(); i++) {
                if (inpBin.charAt(i) > '1') {   /* value must be a binary */
                    System.out.println("Input must be a Binary number");
                    System.out.println();
                    process();
                    break;  
                } else if (i == inpBin.length()-NO1) {
                    System.out.print(inpBin);
                    System.out.println("\n" + "Base 2 Equals");
                    fact();
                }
            }       
        }
    } else {
        System.out.println("Input must be smaller than 2147483647");
    }
}

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private int inpNum;         // value of input 
private int baseNum;        // used to obtain the value of decimal
private int mulNum;         // used to shift when calculate
private String inpBin;      // the String value of inpNum

在getInput()里将键盘输入的值赋给inpNum，并转化为String值给inpBin
但在testInput()里，inpNum就自动变成了0，inpBin的值还是刚刚赋予的值，这是为什么呢？

你搞错了

你这样int inpNum = in.nextInt(); 是在getInput方法定义一个局部变量

修改为inpNum = in.nextInt();

代码如下
[code="java"] void getInput() {
Scanner in = new Scanner(System.in);
System.out.print("Input a binary number: ");
[color=red]inpNum = in.nextInt(); [/color]
inpBin = String.valueOf(inpNum);
}

void testInput() {

if (inpNum < NO3) { /* value must in the scope of int /
if (inpNum < NO0) { / value must bigger than 0 /
System.out.println("Input must be >=0" + "\n");
process();
} else if (inpNum == NO0) { / if value equals 0 /
System.out.println("0");
System.out.println("Base 2 Equals");
System.out.println("0");
System.out.println("Base 10");
} else {
for (int i=NO0; i if (inpBin.charAt(i) > '1') { / value must be a binary */
System.out.println("Input must be a Binary number");
System.out.println();
process();
break;
} else if (i == inpBin.length()-NO1) {
System.out.print(inpBin);
System.out.println("\n" + "Base 2 Equals");
fact();
}
}
}
} else {
System.out.println("Input must be smaller than 2147483647");
}
}

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private int inpNum; // value of input
private int baseNum; // used to obtain the value of decimal
private int mulNum; // used to shift when calculate
private String inpBin; // the String value of inpNum [/code]

String是对象，引用传递
int等基本类型按值传递。
[url]http://blog.csdn.net/faintbear/archive/2004/11/29/198021.aspx[/url]