dot . on numbers

Using Arduino Project Guidance
#1

Hello everyone. I make some calculations on my arduino. Like the distance and speed. I get correct anwsers but I cant find a way to put the .(dot) on my calculations. For example i have 157m instead of 15.7 or 11km/h instead of 1.1km/h

Here is my code:

char buf[16];
unsigned long speed;
unsigned long distance;

speed = gps.speed();
if (speed > 1000) speed = 0;
sprintf(buf, "SPEED:%d km/h ", (int)(distance / 30));
lcd.LCD_write_string(0, 4, buf, MENU_NORMAL);

long distance = sqrt((lat - originLat) * (lat - originLat) + (lon - originLon) * (lon - originLon));
sprintf(buf, "DST: %ld m ", distance);
lcd.LCD_write_string(0, 5, buf, MENU_NORMAL);

how can i put the . on my answers?

Thank you.

#2

type long (signed or unsigned) is an integer. Use type float or double.

#3

Note that the arduino's sprintf does not support floating point for code size reasons. You'll need something such as dtostrf to produce your strings.

#4

I didnt find a way to put a dot. I found another example of someone that he put a dot on latitude or longitude with this way:

"LAT:%d.%05ld",

and on the lcd is displayed like 123.12345

well i want to display for example 157. How do I put the dot to be 15.7 with this way?
i guess it is like %d.%01d?? But it shows me wrong calculations

#5

We call the dot a decimal point.

If you are starting with an integer, you can reduce it to two integer variables like this:

int value = 157;
int tens = value/10; //15
int units = value%10; //7

then print the two variables tens and units in one statement, using the format string "%d.%01d" and you will get 15.7
This will work properly only for positive numbers.

#6