C + XINU - 打印的int类型与鲁％ [英] Printing int type with %lu - C+XINU

问题描述

我有一个给定的code，在我看来，有什么不对的code：
我编译下XINU。

I have a given code, in my opinion there is something wrong with that code: I compile under XINU.

接下来的变量是相关的：

The next variables are relevant :

unsigned long ularray[];
int num;
char str[100];

有一个函数返回INT：

There is a function returns int:

int func(int i)
{
    return ularray[i];
}

现在的code是这样的：

now the code is like this:

num = func(i);
sprintf(str, "number = %lu\n", num);
printf(str);

问题是我得到大的数字，同时与陆％，这是不正确的打印。

The problem is I get big numbers while printing with %lu, which is not correct.

如果我改变的％禄为％d个后，我得到了正确的号码。
例如：用％lu个我得到27654342，同时与％D我得到26，后者是正确的;

If i change the %lu to %d, i get the correct number. For example: with %lu i get 27654342, while with %d i get 26, the latter is correct;

变量给出，该函数的声明中给出，我写的身体，但它必须返回INT;

The variables are given, the declaration of the function is given, i write the body but it must return int;

我的问题是：

1. 我不熟悉的sprintf也许这个问题是存在的？

1. I'm not familiar with 'sprintf' maybe the problem is there?

我分配unsigned long类型为int，然后打印用％lu个整型，是正确的？

I assigned unsigned long to int and then print the int with %lu, is That correct?

我该如何解决这个问题呢？

How can i fix the problem?

先谢谢了。

谢谢大家的回答。
我只想说，我在工作XINU，以及我改变了文件的编译的顺序，你知道什么？其工作，并显示在％鲁％d个相同的数字。

Thanks everyone for answering. I just want to mention I'm working under XINU, well i changed the order of the compilation of the files and what you know... its working and showing same numbers on %lu and %d.

我清楚地知道，分配unsigned long类型为int，然后用％lu个印刷是不正确的编码，可能会导致数据丢失。
但正如我所说，code给定，我不能改变的变量和打印命令。

I'm well aware that assigning 'unsigned long' to int and then printing with %lu is incorrect coding and may result loss of data. But as i said, the code is given, i couldn't change the variables and the printing command.

我没有错误或警告BTW。
我不知道为什么改变固定的问题的编译顺序，如果有人有一个想法，你更然后欢迎大家分享。

I had no errors or warnings btw. I have no idea why changing the compilation order fixed the problem, if someone have an idea you are more then welcome to share.

我要感谢大家谁试图帮助我。

I want to thank all of you who tried to help me.

推荐答案

1）误解为普通格式说明

1) the misunderstanding is format specifiers in general

2）num是一个int - 因此，％d个是正确的，当一个 INT 是你想要的打印。

2) num is an int -- therefore, %d is correct when an int is what you want to print.

3）理想

• INT FUNC（int i）以将无符号长FUNC（为size_t我）


• 和 INT NUM 将无符号长NUM


• 和的sprintf（STR，数=％d个\\ N，NUM）; 将的sprintf（STR，数=％lu个\\ n，NUM）;

• int func(int i) would be unsigned long func(size_t i)
• and int num would be unsigned long num
• and sprintf(str, "number = %d\n", num); would be sprintf(str, "number = %lu\n", num);

这样一来，就没有缩小，也没有转换 - 类型/值是$正确执行整个$ p pserved

that way, there would be no narrowing and no conversions -- the type/values would be correctly preserved throughout execution.

和是迂腐，的printf 应的printf（％S，STR）;

如果你把你的警告级别一路上涨，你的编译器会警告你一些这些事情。我一直在编程很长一段时间，我还是离开了警戒线令人讨厌高（可以通过一些人的标准）。

if you turn your warning levels way up, your compiler will warn you of some of these things. i have been programming for a long time, and i still leave the warning level obnoxiously high (by some people's standards).

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