निम्नलिखित में से कौन सा एक अमान्य चर है?
Which of the following is an invalid variable?
A)
B)
C)
D)
Explanation:
The invalid variable in the list is:
(D) 1st_string
In most programming languages, variable names cannot start with a number. So, 1st_string is an invalid variable name because it starts with a digit (1).
The other options are valid variable names:
- (A) my_string_1: This is valid.
- (B) foo: This is valid.
- (C) __: This is valid, though it's often used for special purposes in some languages (like Python).