If you mean a variable name, then no -- it must begin with a letter or an underscore, but any combination of letters, digits and underscores may follow.
If you mean a variable that stores an identifier, then yes -- so long as the identifier is a string type.
Identifiers refers to the names of variables, functions and array. These are user defined names and consist of a sequence of letters and digits, with a letters as a first character.Both uppercase and lowercase letters are permitted, although lowercase letters are commonly used. The underscore character is also permitted in identifiers. It is usually used as a link between two words in long identifiers. In C, identifiers may contain any alphanumeric characters (a-z, A-Z, 0-9) as well as underscores (_), but must not begin with a number.
The execution character set is composed from the printable ASCII characters. However, not all printable characters can actually be used as identifiers; only the letters, underscore and digits may be used. Furthermore, an identifier cannot begin with a leading digit because a leading digit would signify that the digit is the most-significant digit of a numeric value. Allowing leading digits in identifiers would over-complicate the language parser.
An identifier starts with one of [_, a-z, A-Z] and may continue with one or more of [_, a-z, A-Z, 0-9]. There are often length limitations as well as limitations involving leading underscores, [_], and identifiers may not exactly match any reserved word.
It's by design; this way the lexical parser is able to decide that any given string is a keyword or an identifier.
keywords:- every word in a c program is either a keyword or an identifier. All keywords are basically the sequences of characters that have one or fixed meanings. And these meanings in any circumtances , can't be changed. All c keywords must be written in lowercase (small) letters. eg:- auto, break ,case, char, const, do, if ,double, else .....etc identifiers:- identifiers r names given to program elements such as variables , arrays & functions. Basically identifers r the sequences of alphabets or digits. Rules for forming identifier name * the first character must be analphabet (uppercase or lowercase) or an underscore * all succeeding characters must be letters or digits. * no special characters or punctuatio symbols are allowed except the underscore"_". * no two successive underscores are allowed. * keywords shouln't be used as identifiers.
Identifiers refers to the names of variables, functions and array. These are user defined names and consist of a sequence of letters and digits, with a letters as a first character.Both uppercase and lowercase letters are permitted, although lowercase letters are commonly used. The underscore character is also permitted in identifiers. It is usually used as a link between two words in long identifiers. In C, identifiers may contain any alphanumeric characters (a-z, A-Z, 0-9) as well as underscores (_), but must not begin with a number.
An identifier is a combination of alpha numeric characters, the first being the letter of an alphabet or an underline, and the remaining being any letter of the alphabet, any numeric digit, or the underline. An Identifier is a name for a variable, type, type member, template, class, function, namespace etc and is usually limited to letters, digits and underscores..
the numbers 0 through 9 written in sequence or any portion of that sequence
It has not yet been proven whether any arbitrary sequence of digits appears somewhere in the decimal expansion of pi.
It can be 53.06 with any digit greater than '4' plus any additional sequence of digits after the '6', and it can be 53.07 with any digit less than '5' plus any additional sequence of digits after the '7'. There are an infinite number of them.
%{ #include<stdio.h> int valid=1; %} %token digit letter %% start : letter s s : letter s | digit s | ; %% int yyerror() { printf("\nIts not a identifier!\n"); valid=0; return 0; } int main() { printf("\nEnter a name to tested for identifier "); yyparse(); if(valid) { printf("\nIt is a identifier!\n"); } }
The execution character set is composed from the printable ASCII characters. However, not all printable characters can actually be used as identifiers; only the letters, underscore and digits may be used. Furthermore, an identifier cannot begin with a leading digit because a leading digit would signify that the digit is the most-significant digit of a numeric value. Allowing leading digits in identifiers would over-complicate the language parser.
In numerology, any repeating sequence of numbers is a good sign. In cursory research, the term 'angel numbers' came up quite a bit. In angelology, the sequence of numbers, especially the number 7, in digits of three or more is considered to be very lucky.
An identifier starts with one of [_, a-z, A-Z] and may continue with one or more of [_, a-z, A-Z, 0-9]. There are often length limitations as well as limitations involving leading underscores, [_], and identifiers may not exactly match any reserved word.
There are short strings of digits which will repeat, but there is no sequence which will repeat forever.
Any number that repeats the same sequence of digits over and over again is rational. Note that it need not start with the repeated sequence of digits; the repetition may start after a certain point; such a number would also be rational, for example 0.88204204204204204...
You can make 916,132,832 different five-character passwords if the code can be a mixture of letters and digits in any order and is case sensitive.