Double data types

[Bay]

How to display the float number with 9 decimal places. example: 0.123456789

I have tried with below code, but the terminal displays The number is lf.

double number1=0.123456789;

PRINTF("The number is %lf", number1);

[frank_m]

As Alice_Yang suggested, just specifiy the precision in the format string.
If you don't, the default value (usually 6 digits) is used.

> Double data types

> How to display the float number with 9 decimal places. example: ...

I hope you realized that "double" and "float" are different types of different size.
Only "float" is natively supported by Cortex M FPUs, and several clib implementations (i.e. printf()/scanf()) have no or limited support for "double" either.
Check the respective library documentation.

[Alice_Yang · Accepted solution]

Hello @Bay 

How about PRINTF("The number is %.9f", number1);.

https://community.nxp.com/t5/LPC-Microcontrollers/LPC54628-Printf-Floating-numbers-doesnt-have-minus...  

BR

Alice

[Bay]

Hi Alice,
Thanks. It works.
How about if the user enters unknown number of decimal places?
How should write in this code line?
SCANF("%f ",&number1);
Why is the double data type not using %lf?