2.4.1 Decimal Literals
Syntax
digit ::= 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
 
An 
exponent 
for an integer literal shall not have a minus sign. 
 
Static Semantics
An underline character in a 
numeric_literal 
does not affect its meaning. The letter E of an 
exponent 
can be written either in lower case or in upper case, with the same meaning. 
 
Examples
Examples of decimal 
literals: 
12        0      1E6    123_456    --  integer literals
12.0      0.0    0.456  3.14159_26 --  real literals
Ada 2005 and 2012 Editions sponsored in part by Ada-Europe