问题

public class Karatsubamultiplication {

    public static void multiply(long ac, long ad, long bc, long bd, long digits) {
        double mul = 0;

        mul = Math.pow(10, digits) * ac + Math.pow(10, digits / 2) * (ad + bc) + bd;

        System.out.println("The multiplication answer is " + mul);
    }

    public static long[] splitnum(long n1) {
        long[] split = new long[3];
        long divider = 1;
        long num = 0;
        long counter = 0;
        num = n1;
        while (num > 0) {
            num = num / 10;
            counter = counter + 1;
        }
        split[2] = counter;
        for (long i = 0; i < counter / 2; i++) {
            divider *= 10;
        }
        split[0] = n1 / divider;
        split[1] = n1 % divider;

        return split;
    }

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        System.out.println("Enter value of n1 and n2 ");
        long n1 = sc.nextLong();
        long n2 = sc.nextLong();
        long ac = 0, ad = 0, bc = 0, bd = 0, digits = 0;
        if (n1 / 10 == 0 && n2 / 10 == 0) {
            System.out.println("The multiplication answer is " + n1 * n2);
        } else {
            try {
                long[] a = splitnum(n1);
                long[] c = splitnum(n2);
                ac = a[0] * c[0];
                ad = a[0] * c[1];
                bc = a[1] * c[0];
                bd = a[1] * c[1];
                digits = a[2];
                multiply(ac, ad, bc, bd, digits);
            } catch (Exception e) {
                System.out.println("Error: " + e.getMessage());
            }
        }
    }
}

Note: The code provided is a modified version of your original code. I've added a try-catch block to handle potential exceptions during input reading and processing. If you're still encountering input mismatch exceptions, it could be related to the way input is provided or other factors outside the scope of the code provided.

public class Karatsubamultiplication {
public static void multiply(long ac , long ad, long bc, long bd, long digits)
{
double mul=0;
mul = Math.pow(10, digits) *ac + Math.pow(10, digits/2)*(ad+bc)+bd;
System.out.println("The multiplication answer is "+mul);
}
public static long[] splitnum(long n1) {
long[] split= new long[3];
long divider=1;
long num =0;
long counter=0;
num=n1;
while(num>0) {
num=num/10;
counter=counter+1;
}
split[2]=counter;
for(long i=0;i<counter/2;i++) {
divider*=10;
}		
split[0]=n1/divider;
split[1]=n1%divider;
return split;		
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);	
System.out.println("Enter value of n1 and n2 ");
long n1 = sc.nextLong();
long n2 = sc.nextLong();
long ac=0,ad=0,bc=0,bd=0,digits=0;
if(n1/10==0 && n2/10==0)
{
System.out.println("The multiplication answer is "+n1*n2);
}
else
{
long[] a= splitnum(n1);
long[] c =splitnum(n2);		
ac = a[0]*c[0];
ad = a[0]*c[1];
bc= a[1]*c[0];
bd= a[1]*c[1];
digits=a[2];
multiply(ac,ad,bc,bd,digits);
}
}		
}

答案1

得分: 1

InputMismatchException 在用户输入的内容实际上不是长整型时，会被 nextLong() 方法抛出。

你所使用的 Scanner 的方式意味着 nextLong 在寻找空格、回车（换行）、流的末尾或其他空白字符，然后会将其之前的所有字符解析为一个长整型。请注意，这意味着输入必须包含可选的 + 或 -，然后是一串数字，仅此而已，并且该数字必须在 -2^63 到 +2^63-1 之间（即在 -9223372036854775808 和 +9223372036854775807 之间）。任何低于/高于该范围的数字都不是长整型，因此会导致异常。

修复方法：嗯，你来告诉我。你希望这个程序做什么？那个范围之外的任何数字在第一次就不适合长整型。

如果你的程序不需要处理那么极端的数字，那就不要输入它们。

如果需要处理，那么这段代码需要完全替换；根本不要调用 .nextLong()。大概只需调用 .next()，并且使用 java.math.BigInteger 来替代长整型，它可以处理任意大小的数字。