数据结构6：斐波那契数列，递归算法，求和算法专题

package ch06;

public class Fibonacci {
public static int getNumber(int n) {
if(n == 1) {
return 0;
} else if(n == 2){
return 1;
} else {
return getNumber(n - 1) + getNumber(n - 2);
}
}
}

package ch06;

public class Recursion {
public static void main(String[] args) {
test2(100);
}

public static void test() {
System.out.println("Hello,World!");
test();
}

public static void test2(int n) {
if(n == 0) {
return;
}
System.out.println(n);
test2(n - 1);
}
}

package ch06;

public class Triangle {

public static int getNumber(int n) {
int total= 0;
while(n > 0) {
total = total + n;
n--;
}
return total;
}

public static int getNumberByRecursion(int n) {
if(n == 1) {
return 1;
} else {
return n + getNumberByRecursion(n - 1);
}
}
}