华为上机题java源码6

public class MyMultiply {
/**
* @param args
*/
public static void main(String[] args) {
// System.out.println("Hello world");
//String str1 = "1234";
//String str2 = "1234";
//String str1 = "1076060999";
//String str2 = "90188905567";
String str1 = "23456789009877666555544444";
String str2 = "346587436598437594375943875943875";
int len1 = str1.length();
int len2 = str2.length();
char[] s1 = str1.toCharArray();
char[] s2 = str2.toCharArray();
// 高低位对调
covertdata(s1, len1);
covertdata(s2, len2);
System.out.println("乘数："+str1);
System.out.println("乘数："+str2);
multiply(s1, len1, s2, len2);
}
public static void covertdata(char data[], int len) {
//高低位对调
for (int i = 0; i < len / 2; i++) {
data[i] += data[len - 1 - i];
data[len - 1 - i] = (char) (data[i] - data[len - 1 - i]);
data[i] = (char) (data[i] - data[len - 1 - i]);
}
}
public static void multiply(char a[], int alen, char b[], int blen) {
// 两数乘积位数不会超过乘数位数和+ 3位
int csize = alen + blen + 3;
// 开辟乘积数组
int[] c = new int[csize];
// 乘积数组填充0
for (int ii = 0; ii < csize; ii++) {
c[ii] = 0;
}
// 对齐逐位相乘
for (int j = 0; j < blen; j++) {
for (int i = 0; i < alen; i++) {
c[i + j] += Integer.parseInt(String.valueOf(a[i]))* Integer.parseInt(String.valueOf(b[j]));
}
}
int m = 0;
// 进位处理
for (m = 0; m < csize; m++) {
int carry = c[m] / 10;
c[m] = c[m] % 10;
if (carry > 0)
c[m + 1] += carry;
}
// 找到最高位
for (m = csize - 1; m >= 0;) {
if (c[m] > 0)
break;
m--;
}
// 由最高位开始打印乘积
System.out.print("乘积：");
for (int n = 0; n <= m; n++) {
System.out.print(c[m - n]);
}
System.out.println("");
}
}