采用for嵌套循环如何写下面两个代码？？？？？？？？？？？

[一只红烧虾]

[一只红烧虾]

引用 2 楼 SpringLiangSy的回复:

System.out.println("请输入一个1到15之间的整数"); Scanner scanner = new Scanner(System.in); int num = scanner.nextInt(); for (int i = 1; i <=num; i++) { for (int j = num; j >i; j--) { System.out.print(" "); } for (int j = i; j >=1; j--) { System.out.print(j); } for (int j = 2; j <=i; j++) { System.out.print(j); } System.out.println(); }

谢谢！！！！！！！！！！！！！！！

[一只红烧虾]

引用 1 楼 lyqiang00的回复:

public static void pi(int count) {
double sum = 0;
for(int i=1; i<=count; i++) {
int a = i % 2 == 0 ? -1 : 1 ;
sum += a / (2*(double)i - 1);
}
System.out.println(4 * sum);
}

谢谢！！！！！！！！！！！！！！！！！

[x541888]

System.out.println("请输入一个1到15之间的整数");
Scanner scanner = new Scanner(System.in);
int num = scanner.nextInt();
for (int i = 1; i <=num; i++) {
for (int j = num; j >i; j--) {
System.out.print(" ");
}
for (int j = i; j >=1; j--) {
System.out.print(j);
}
for (int j = 2; j <=i; j++) {
System.out.print(j);
}
System.out.println();
}

[略知java的景初]

int n;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        sc.close();
        double p = 0.0;
        for (int i = 1; i < n; i++) {
            if (i % 2 == 1) {
                p += (double) 1 / (2 * i - 1);
            } else {
                p +=(double) -1 / (2 * i - 1);
            }
        }
        p = p * 4;
        System.out.println(p);

[略知java的景初]

for (int n = 10000; n < 1000001; n = n + 10000) {
            double p = 0.0;
            for (int i = 1; i < n; i++) {
                if (i % 2 == 1) {
                    p += (double) 1 / (2 * i - 1);
                } else {
                    p += (double) -1 / (2 * i - 1);
                }
            }
            p = p * 4;
            System.out.println("当n=" + n + "时,p=" + p);
        }

[lyqiang00]

public static void pi(int count) {
double sum = 0;
for(int i=1; i<=count; i++) {
int a = i % 2 == 0 ? -1 : 1 ;
sum += a / (2*(double)i - 1);
}
System.out.println(4 * sum);
}

[SpringLiangSy]

System.out.println("请输入一个1到15之间的整数"); Scanner scanner = new Scanner(System.in); int num = scanner.nextInt(); for (int i = 1; i <=num; i++) { for (int j = num; j >i; j--) { System.out.print(" "); } for (int j = i; j >=1; j--) { System.out.print(j); } for (int j = 2; j <=i; j++) { System.out.print(j); } System.out.println(); }