# Keywords and Builtin Constants

### KEYWORDS

Version 1.0 of ALADDIN has only 10 keywords, namely:
```     break,        else,         for,      if,    print,
quit,  SetUnitsOn, SetUnitsOff,    then,    while
```

SI and US Units

The following names are reserved for SI and US units:

```SI Units   micron, mm,	cm, dm, m, km, g, kg, mg, N, kN, kgf,
Pa, kPa, MPa, GPa, deg_C, DEG_C, Jou, kJ, Watt, kW,
Hz, rpm, cps

US Units   in, ft, yard, mile, mil, micro_in, lb, klb, ton,
grain, lbf, kips,  psi, ksi, deg_F, DEG_F, gallon,
barrel, sec,  ms,  min,  hr, deg, rad
```

Some Remarks

• The keywords if , then , and else , are used in the construction of branching constructs, and for , and while in looping constructs.
• The keyword break forces an early exit from a looping construct.
• The keyword quit terminates the program execution.
• As their names suggest, the keywords SetUnitsOn and SetUnitsOff turn the units checking on, and off.
• You should not use reserved word names, or names of units, for variable names in ALADDIN input files.

### BUILTIN CONSTANTS

```    Name                Value                            Purpose
============================================================

DEG      57.29577951308      Radians to degrees conversion
E      2.718281828459
GAMMA      0.577215664901
PI      3.141592653589
```

Example 1 : The script of code

```    print "1 radian = ", DEG, "degrees \n";
quit;
```
generates the output
```    1 radian =       57.3 degrees
```

Example 2 : To compute the area of a circle, we coupld write:

```    radius = 3 cm;

```    circle radius is =          3 cm