#Dyalog APL, 32 33 bytes

⍕¨{⍵-3↑31 11≡2↑⍵}31 12 1E4⌊⍎∊⍕⌽¨⎕

I/O is list of three strings ('dd' 'mm' 'yyyy').

TryAPL, but note that ⎕ (prompt for input) has been replaced with ⍵ and the entire line enclosed in {...} to enable online testing, and ⍎ (execute expression) has been replaced with 2⊃⎕VFI (verify and fix input) because execution of arbitrary code is blocked.

Dyalog APL, 32 33 bytes

⍕¨{⍵-3↑31 11≡2↑⍵}31 12 1E4⌊⍎∊⍕⌽¨⎕

I/O is list of three strings ('dd' 'mm' 'yyyy').

TryAPL, but note that ⎕ (prompt for input) has been replaced with ⍵ and the entire line enclosed in {...} to enable online testing, and ⍎ (execute expression) has been replaced with 2⊃⎕VFI (verify and fix input) because execution of arbitrary code is blocked.

#Dyalog APL, 32 bytes

{⍵-3↑31 11≡2↑⍵}31 12 9999⌊⍎∊⍕⌽¨⎕

Prompts for input in the format 'dd' 'mm' 'yyyy' and returns a list of three numbers.

TryAPL, but note that ⎕ (prompt for input) has been replaced with ⍵ and the entire line enclosed in {...} to enable online testing, and ⍎ (execute expression) has been replaced with 2⊃⎕VFI (verify and fix input) because execution of arbitrary code is blocked.

#Dyalog APL, 32 33 bytes

⍕¨{⍵-3↑31 11≡2↑⍵}31 12 1E4⌊⍎∊⍕⌽¨⎕

I/O is list of three strings ('dd' 'mm' 'yyyy').

TryAPL, but note that ⎕ (prompt for input) has been replaced with ⍵ and the entire line enclosed in {...} to enable online testing, and ⍎ (execute expression) has been replaced with 2⊃⎕VFI (verify and fix input) because execution of arbitrary code is blocked.

#Dyalog APL, 32 bytes

{⍵-3↑31 11≡2↑⍵}31 12 9999⌊⍎∊⍕⌽¨⎕

Prompts for input in the format 'dd' 'mm' 'yyyy' and returns a list of three numbers.

#Dyalog APL, 32 bytes

{⍵-3↑31 11≡2↑⍵}31 12 9999⌊⍎∊⍕⌽¨⎕

Prompts for input in the format 'dd' 'mm' 'yyyy' and returns a list of three numbers.

TryAPL, but note that ⎕ (prompt for input) has been replaced with ⍵ and the entire line enclosed in {...} to enable online testing, and ⍎ (execute expression) has been replaced with 2⊃⎕VFI (verify and fix input) because execution of arbitrary code is blocked.