带无符号字符的模运算符 [英] modulus operator with unsigned chars

问题描述

试图让一些代码工作而模数不想做我想要它做的事情......这意味着我错了.

我有 unsigned char 我试图将小时/分钟/秒分开，以便我可以在屏幕上以 Ascii 显示它们.

变量secs 是一个unsigned int.其他一切都是无符号字符.我想要 unsigned char 的结果，以免浪费内存.在嵌入式环境中工作.

有人愿意看看代码片段并告诉我我做错了什么吗?

hours = secs/3600.0;分钟 =(秒/60.0)-(小时*3600)；秒=秒-(小时*3600)-(分钟*60)；sec_ones =(unsigned char)((秒%10));sec_tens =(unsigned char)((seconds-sec_ones)%100);min_ones =(无符号字符)(分钟％10)；min_tens =(unsigned char)((minutes-min_ones)%100);hrs_ones =(无符号字符)(小时%10)；hrs_tens =(unsigned char)((hours-hrs_ones)%100);

解决方案

minutes =(secs/60.0)-(hours*3600);

应该

minutes =(secs/60.0)-(hours*60);

除此之外，它适用于足够小的输入:http://ideone.com/VPKP1

不过，有些事情我会改变.例如，进行双除法然后将结果分配回 unsigned char 是没有意义的，您还不如只进行整数除法.

Trying to get some code working and the modulus doesn't want to do what I want it to do... which means I have it wrong.

I have unsigned chars that I'm trying to seperate out hours/minutes/seconds into so I can display them on the screen in Ascii.

The variable secs is anunsigned int. Everything else is anunsigned char. I want the results in unsigned chars so not to waste memory. Working in an embedded environment.

Anyone care to look at the code snippet and tell me what I've done wrong?

hours   = secs/3600.0;
minutes =(secs/60.0)-(hours*3600);
seconds =secs-(hours*3600)-(minutes*60);

sec_ones    =(unsigned char)((seconds%10));
sec_tens    =(unsigned char)((seconds-sec_ones)%100);
min_ones    =(unsigned char)(minutes%10);
min_tens    =(unsigned char)((minutes-min_ones)%100);
hrs_ones    =(unsigned char)(hours%10);
hrs_tens    =(unsigned char)((hours-hrs_ones)%100);

解决方案

minutes =(secs/60.0)-(hours*3600);

should be

minutes =(secs/60.0)-(hours*60);

Other than that, it works for small enough input: http://ideone.com/VPKP1

There are some things that I'd change, though. For example, there's no point doing a double division and then assigning the result back to unsigned char, you might as well just do integer division.

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