# CoCoA:FloatStr

## FloatStr

convert rational number to a float string

### Description

These two functions convert a rational number X into a (decimal)

floating point string. The optional second argument Prec says how many

decimal digits to include in the mantissa; the default value is 10. Note that an exponent is always included; the only exception being the number zero which is converted to the string 0.

#### Example

```  FloatStr(2/3);         -- last printed digit is rounded
6.666666667*10^(-1)
-------------------------------
FloatStr(7^510);       -- no arbitrary limit on exponent range
1.000000938*10^431
-------------------------------
FloatStr(1/81, 50);    -- precision of mantissa specified by user
1.2345679012345679012345679012345679012345679012346*10^(-2)
-------------------------------
FloatStr(1/2);         -- trailing zeroes are not suppressed
5.000000000*10^(-1)
-------------------------------
```

### Syntax

```FloatStr(X:RAT):STRING
FloatStr(X:RAT, Prec:INT):STRING
```

```   <type>rat</type>
<type>string</type>
```