java 使用 for 循环打印数字
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Using a for-loop to print numbers
提问by JDB
I'm trying to write a program that prints all numbers from 0 to 1,000 where the number mod 5 = 3. This is what I have so far
我正在尝试编写一个程序，打印从 0 到 1,000 的所有数字，其中数字 mod 5 = 3。这就是我目前所拥有的
public class NewMain {
public static void modNumbers(int i)
{
}
public static void main(String[] args) {
for(int i = 0; i > 1000; i++)
{
if(i%5 = 3)
{
System.out.println(i);
}
}
}
}
I'm not getting any output, so I know I'm doing something wrong. Should I have a return type in the method?
我没有得到任何输出，所以我知道我做错了什么。我应该在方法中有返回类型吗？
回答by Cooper
Change it from:
将其更改为：
for (int i = 0; i > 1000; i++)
to
到
for (int i = 0; i < 1000; i++)
Essentially, the loop never begins because the loop invariant is false (as i is less than 1000), and your print statement is never reached because the loop never initializes.
本质上，循环永远不会开始，因为循环不变式为假（因为 i 小于 1000），并且永远不会到达您的打印语句，因为循环永远不会初始化。
Additionally, as WTP mentioned, use == for numeric comparisons (an important note is that you use string1.equals(string2) or compareTo with Strings, just for your future reference).
此外，正如 WTP 所提到的，使用 == 进行数字比较（一个重要的注意事项是您将 string1.equals(string2) 或 compareTo 与字符串一起使用，仅供您将来参考）。
回答by Jochen Bedersdorfer
for(int i = 0; i < 1000; i++)
for(int i = 0; i < 1000; i++)
回答by melhosseiny
Here's what you have to do:
这是你必须做的：
- Change
i > 1000toi <= 1000asistarts with 0 and increments up to 1000. - Change
i%5 = 3toi%5 == 3as the first is doing an assignment while the second is comparing for equality.
- 更改
i > 1000为i <= 1000asi从 0 开始并递增到 1000。 - 更改
i%5 = 3为，i%5 == 3因为第一个正在执行任务，而第二个正在比较相等性。
回答by ratchet freak
if(i%5 == 3)
single = is for assignment
单个 = 用于赋值
回答by ratchet freak
This:
这：
if(i%5 = 3)
Has to be this:
必须是这样的：
if(i%5 == 3)
You are trying to set something instead of comparing it.
您正在尝试设置某些东西而不是比较它。
回答by Brian Patterson
Need to change the > in your for statement to a < and also the = in your if statement is an assignment operator. Use a comparative operator == or === ... Hope this helps. :)
需要将 for 语句中的 > 更改为 <，并且 if 语句中的 = 是赋值运算符。使用比较运算符 == 或 === ...希望这会有所帮助。:)
回答by Cosmin Cosmin
for (int i = 0; i <1000; i++)
for (int i = 0; i <1000; i++)
回答by idungotnosn
You have two problems:
你有两个问题：
1.
1.
for(int i = 0; i > 1000; i++)
The for loop only starts when i is greater than 1000, but the initial value for i is less than one thousand. The code will not work.
for 循环只在 i 大于 1000 时开始，但 i 的初始值小于 1000。该代码将不起作用。
2.
2.
if(i%5 = 3)
You need this to have two equal signs so that it becomes a statement that returns a true or false value. Your code would look like this after making the corrections:
您需要它具有两个等号，以便它成为返回真值或假值的语句。进行更正后，您的代码将如下所示：
for(int i = 0; i < 1000; i++)
{
if(i%5 == 3)
{
System.out.println(i);
}
}
回答by Karel Petranek
Another little detail:
还有一个小细节：
i%5 = 3
should be
应该
i%5 == 3
