convert Unsigned Int to array of chars (String)

Question

EDIT: I am using this for programming a pic, so the C will be quite limited. The compiler is XC8.

Following function expects me to pass a string:

void OLED_string(char* str, short x, short y) {

    short pos = 0;
    char character = str[pos++];
    short startx = x;
    short starty = y;
    while(character != '\0') {
        OLED_char(character, startx, starty);
        if(startx >= 123) starty++; //wrap around
        startx += 5;
        character = str[pos++];
    }
}

I would like to display a value I have in a unsigned Integer. This value should be converted to Float and then divided by ten. Since float is very slow I would prefer to convert the integer to a string, and then simply add a point before the last character. I tried to pass directly the integer to this function but it does not work. Thanks!

Answer 1

If you can use C standard library functions, sprintf() should handle the string conversion. Instead of adding the decimal point by shuffling characters around, you could use integer arithmetic:

char str[20];
unsigned int value = 105;

sprintf(str, "%u.%u", value / 10, value % 10);

Integer division won't be fast, but it should be faster than floating point. And I suspect that the int -> string conversion algorithm will be doing division anyway.

Answer 2

The itoa function is your friend. http://www.cplusplus.com/reference/cstdlib/itoa/

Answer 3

itoa and ftoa functions are both in stdlib.h in XC8 compiler so they will work on PIC. Just include <stdlib.h>

Answer 4

ITOA bei XC8:

int main(void) {
  char Buffer[7];
  int i = 12345;
  itoa(Buffer, i, 10);
  UART_Write_Text_NL((uChr)Buffer); 
  return;
}