剛翻了一下新版的 C18 發現已經有支援浮點數的運算了，底下為 copy 使用手冊裡有關浮點數的片斷:
5.2 32-BIT FLOATING POINT MATH LIBRARY
The basic floating point operations—add, subtract, multiply, divide and conversions
between floats and integers—comply with the IEEE 754 standard for single precision
floats with two exceptions. The exceptions will be discussed under Subnormals
(Section 5.2.1.2 “Subnormals”) and Rounding (Section 5.2.2 “Rounding”). The
extended mode and traditional mode use the same float representations and the
results of float operations are the same.
The IEEE standard for binary floating-point arithmetic published in 1985 became
known officially as ANSI/IEEE Std 754-1985 [IEEE85]. The standard has three
important requirements:
• consistent representation of floating-point numbers by all machines adopting the
standard;
• correctly rounded floating-point operations, using various rounding modes;
• consistent treatment of exceptional situations such as division by zero.

C18 不支援浮點運算，而且 Printf( ) 也只有到 long 而已。
到這裡找一下看看:
http://www.piclist.com/techref/microchip/math/basic.htm

您好：
請問我要使一個數值（long 或unsigned long）做一連串加減乘除，再把他顯示到led上去，目前遇到兩個問題

第一個是我如何把數值作除法變float？
第二個是我知道可以把long用ltoa 把數值轉成string,在放到lcd上
但如何把float 弄成string呢？
謝謝