题目:利用递归方法求5!。
程序分析:递归公式:fn=fn_1*4!
程序设计:
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import java.util.Scanner;
public class Ex22 {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
int n = s.nextInt();
Ex22 tfr = new Ex22();
System.out.println(tfr.recursion(n));
}
public long recursion( int n) {
long value = 0 ;
if (n == 1 || n == 0 ) {
value = 1 ;
} else if (n > 1 ) {
value = n * recursion(n- 1 );
}
return value;
}
}
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方法二利用递归方法求5!。
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public class lianxi22 {
public static void main(String[] args) {
int n = 5 ;
rec fr = new rec();
System.out.println(n+ "! = " +fr.rec(n));
}
}
class rec{
public long rec( int n) {
long value = 0 ;
if (n == 1 ) {
value = 1 ;
} else {
value = n * rec(n- 1 );
}
return value;
}
}
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