Arduino sprintf 浮点数未格式化 [英] Arduino sprintf float not formatting
问题描述
我有这个 arduino 草图,
I have this arduino sketch,
char temperature[10];
float temp = 10.55;
sprintf(temperature,"%f F", temp);
Serial.println(temperature);
温度打印为
? F
关于如何格式化这个浮点数的任何想法?我需要它是一个字符字符串.
Any thoughts on how to format this float? I need it to be a char string.
推荐答案
由于某些性能原因,%f
未包含在 Arduino 的 sprintf()
实现中.更好的选择是使用 dtostrf()
- 您将浮点值转换为 C 样式字符串,方法签名如下所示:
Due to some performance reasons %f
is not included in the Arduino's implementation of sprintf()
. A better option would be to use dtostrf()
- you convert the floating point value to a C-style string, Method signature looks like:
char *dtostrf(double val, signed char width, unsigned char prec, char *s)
使用此方法将其转换为C-Style字符串,然后使用sprintf,例如:
Use this method to convert it to a C-Style string and then use sprintf, eg:
char str_temp[6];
/* 4 is mininum width, 2 is precision; float value is copied onto str_temp*/
dtostrf(temp, 4, 2, str_temp);
sprintf(temperature,"%s F", str_temp);
您可以更改最小宽度和精度以匹配您要转换的浮点数.
You can change the minimum width and precision to match the float you are converting.
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