MCUXpresso General中的主题 dtostrf function

dtostrf function

josephg — Fri, 31 May 2019 09:28:10 GMT

I am tried to use the dtostrf() function to convert a floating variable to a string array but I am getting the following error ../source/AdcSdkLcd.c:128:9: warning: implicit declaration of function 'dtostrf'; did you mean 'strstr'? [-Wimplicit-function-declaration]. What should I do to convert a floating variable to a string array?

Details:

Using MCUXpresso 10.3.0 IDE

Using Freedom Development Board FRDM-K22F

Trying to display an ADC voltage on a Hitachi 2X16 HD44780U Dot Matrix Liquid Crystal Display Controller/Driver

I am able to display an integer on the LCD with the itoa() function.

The ADC voltage is displaying correctly on the Tera Terminal.

Re: dtostrf function

converse — Fri, 31 May 2019 17:51:01 GMT

In standard C, you should use sprintf- there are plenty of examples of how to do this.

Re: dtostrf function

josephg — Mon, 03 Jun 2019 10:21:57 GMT

Con Verse,

Thank you for your replay. I cannot get function sprintf to work with a floating variable. It returns a 0.000

Code:

char buffer1[5];

float value1 = 3.123;

sprintf(buffer1,"%5.3f", value1);

PRINTF("\rUsing function sprintf() to convert floating number %f to a string produces the following string: %s\n", value1, buffer1);

Tera Terminal Display:

Using function sprintf() to convert floating number 3.123000 to a string produces the following string: 0.000

Do you have any suggestions?

Thanks,

Joseph Grigaliunas

Re: dtostrf function

converse — Mon, 03 Jun 2019 17:00:01 GMT

To start with your buffer is not long enough - what about the terminating \0?

Re: dtostrf function

josephg — Mon, 03 Jun 2019 19:04:37 GMT

Con Verse,

I'll try increasing the size of the buffer.

I don't understand what terminating \0 means.

Thanks,

Joseph Grigaliunas

Re: dtostrf function

converse — Tue, 04 Jun 2019 08:06:05 GMT

I suggest it is time you learnt about strings in C.

for example

Strings in C