java大數類
阿新 • • 發佈:2018-02-27
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主要的整數和浮點數精度不滿足要求的時候能夠使用java提供的BigInteger類和BigDecimal類。
java.math.BigInteger
java.math.BigInteger提供的方法:
- BigInteger add(BigInteger other)
- BigInteger subtract(BigInteger other)
- BigInteger multiply(BigInteger other)
- BigInteger divide(BigIntegr other)
- int compareto(BigInteger other)
- BigInteger mod(BigInteger other)
static BigInteger valueOf(long x)
valueOf方法能夠將普通的數值轉換為大數值:
BigInteger a=BigInteger.valueOf(100);
輸出febonacci數列
輸出febonacci數列前100項。大約在93項時會超出long的範圍:
public static void fibonacci(){
long[] a=new long[100];
for(int i=0;i<100;i++){
if(i==0){
a[0]=0;
System.out.print(a[i]+"\t");
continue;
}else if(i==1){
a[1]=1;
System.out.print(a[i]+"\t");
continue;
}
a[i]=a[i-1]+a[i-2];
System.out .print(a[i]+"\t");
if((i+1)%5==0){System.out.println("");}
}
}
改進:
public static void fibonacci() {
BigInteger[] a = new BigInteger[200];
for (int i = 0; i < 200; i++) {
if (i == 0) {
a[0] = BigInteger.valueOf(0);
System.out.print(a[i] + "\t");
continue;
} else if (i == 1) {
a[1] = BigInteger.valueOf(1);
System.out.print(a[i] + "\t");
continue;
}
a[i] = a[i - 1].add(a[i - 2]);
System.out.println("第" + i + "項:\t" + a[i] + "\t");
}
}
java大數類