Q. 14. Write which of the following varible names are invalid in FORTRAN?
(i) STOP (June 2001, Dec. 99)
(ii) ROOTZ (June 2001, June 2000, Dec. 99)
(iii) 2RATES (June 2001)
(iv) ROLL2 (Dec. 2001)
(v) PROGRAM (Dec. 2001)
(vi) X + Y (Jan. 2001)
(vii) END (Jan. 2001, June 2000)
(viii) 2ROOT (Jan. 2001)
(ix) Y - 55 (June 2000)
(x) M + 30 (Dec. 99)

Ans. (i) Invalid variable because the keyword of Fortran cannot be used as variable name.
Ans. (ii) Valid variable.
Ans. (iii) Invalid variable because first character must be alphabetic.
Ans. (iv) Valid variable.
Ans. (v) Valid variable.
Ans. (vi) Invalid variable as '+' sign cannot be allowed in the variable name.
Ans. (vii) Invalid variable because the keyword of Fortran cannot be used as variable name.
Ans. (viii) Invalid variable because first character must be alphabetic.
Ans. (ix) Invalid variable as '-' sign cannot be allowed in the variable name.
Ans. (x) Invalid variable as '+' sign cannot be allowed in the variable name.