import java.util.Scanner;
public class TestDemo2 {
//1-100的和
public static int addSum(int n) {
int sum = 0;
for (int i=1;i<=n;i++ ) {
sum += i;
}
return sum;
}
//100以内奇数和和偶数和
public static int addSum2(int n) {
int sum1 = 0;
int sum2 = 0;
for (int i=1;i<=n;i++) {
if(i%2==0){
sum1 += i;
}else{
sum2 += i;
}
}
System.out.println(sum1);//2550
System.out.println(sum2);//2500
return 0;
}
//求1!+2!+3!+4!+5!
public static int facSum(int n) {
int sum = 0;
for (int i=1;i<=n;i++) {
int ret = 1;
for (int j=1;j<=i;j++) {
ret *= j;
}
sum += ret;
}
System.out.println(sum);//153
return 0;
}
//求1!+2!+3!+4!+5!的优化,调用fac(n)
public static int facSum2(int n) {
int sum = 0;
for (int i=1;i<=n;i++) {
sum += fac(i);
}
System.out.println(sum);//153
return sum;
}
//求数字n的阶乘
public static int fac(int n) {
int ret = 1;
for (int j=1;j<=n;j++) {
ret *= j;
}
return ret;
}
public static void main(String[] args) {
int ret = addSum(100);
addSum2(100);
facSum(5);
facSum2(5);
System.out.println(ret);//5050
Scanner scan = new Scanner(System.in);
int a = scan.nextInt();
int ret2 = fac(a);//6
System.out.println(ret2);//720
}
}
Java:一些小练习。
猜你喜欢
转载自blog.csdn.net/yufy0528/article/details/104784452
今日推荐
周排行