Your mission

Write a program that reads a number from its only argument and prints twice its value.

See it in action

./arg_double 21

42

./arg_double 007

14

./arg_double 4 2

wrong number of arguments

Your checklist

• argv[1] contains only the decimal digits 0 to 9, at least one of them, and its value is between 0 and 1000000000. It can start with zeros: 007 is worth 7.
• Print twice that value in decimal, with no leading zero, followed by a newline.
• If the program does not receive exactly one argument (argc must be 2), print wrong number of arguments followed by a newline and exit with status 0.

Your mission

Write a program that reads a number from its only argument and prints twice its value.

See it in action

./arg_double 21

42

./arg_double 007

14

./arg_double 4 2

wrong number of arguments

Your checklist

• argv[1] contains only the decimal digits 0 to 9, at least one of them, and its value is between 0 and 1000000000. It can start with zeros: 007 is worth 7.
• Print twice that value in decimal, with no leading zero, followed by a newline.
• If the program does not receive exactly one argument (argc must be 2), print wrong number of arguments followed by a newline and exit with status 0.