编程题 - 黑马程序员技术交流社区 - 黑马程序员IT技术论坛

public static void main(String[] args) {
try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));) {
System.out.println("请输入[1-9]的整数：");
Integer max = new Integer(bufferedReader.readLine());
if (max >= 1 && max <= 9) {
Integer sum = 0;
StringBuilder stringBuilder = new StringBuilder();
String baseNumber = "2";
for (int i = 0; i < max; i++) {
Integer tmp = new Integer(stringBuilder.append(baseNumber).toString());
if (i == max - 1) {
System.out.print(tmp + "=");
} else {
System.out.print(tmp + "+");
}
sum += tmp;
}
System.out.println(sum);
} else {
throw new RuntimeException("输入数值过大");
}
} catch (NumberFormatException | IOException e) {
System.out.println("输入错误！");
}
}

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