#dc, 10 - 25 = -15

2?A*Ar^1-n

Takes a blank line for "no input".

Calculates 10 ^ (10 * n) - 1, where n is the input, or 2 if input is empty. Prints a string of 9s of the required length.

• 2 push 2 to the stack in case input is empty
• ? push input to the stack
• A push 10 to the stack (dc has shortcuts A-F for 10 - 15)
• * pop twice and multiply (multiply input by 10)
• A push 10 to the stack
• r reverse top two stack elements
• ^ exponentiate 10 ^ (10 * input)
• 1- subtract 1 from the top of stack
• n print with no newline.

dc, 10 - 25 = -15

2?A*Ar^1-n

Takes a blank line for "no input".

Calculates 10 ^ (10 * n) - 1, where n is the input, or 2 if input is empty. Prints a string of 9s of the required length.

• 2 push 2 to the stack in case input is empty
• ? push input to the stack
• A push 10 to the stack (dc has shortcuts A-F for 10 - 15)
• * pop twice and multiply (multiply input by 10)
• A push 10 to the stack
• r reverse top two stack elements
• ^ exponentiate 10 ^ (10 * input)
• 1- subtract 1 from the top of stack
• n print with no newline.

#dc, 10 - 25 = -15

2?A*Ar^1-p

Takes a blank line for "no input".

#dc, 10 - 25 = -15

2?A*Ar^1-n

Takes a blank line for "no input".

Calculates 10 ^ (10 * n) - 1, where n is the input, or 2 if input is empty. Prints a string of 9s of the required length.

• 2 push 2 to the stack in case input is empty
• ? push input to the stack
• A push 10 to the stack (dc has shortcuts A-F for 10 - 15)
• * pop twice and multiply (multiply input by 10)
• A push 10 to the stack
• r reverse top two stack elements
• ^ exponentiate 10 ^ (10 * input)
• 1- subtract 1 from the top of stack
• n print with no newline.