How to add user in Linux with his information

Question

I want to create C application to add user in Linux with useradd command .

I write this code when i use it terminal print error message:

useradd :permission denied
useradd :cannot lock/etc/passwd; try again later 

this is my C code to add user such as i want to add user1 just write user1

char a[50];
char command[150];
fgets(a,sizeof(a),stdin);
strcpy(command,"useradd ");
strcat(command,a);

how i can solve this problem with correct syntax or command?

Answer 1

if sudo package is not installed, You can install it. Or you can create it as a root using su . It will ask root password after that you can use any superuser caommnads.

Answer 2

This is because you need to run the command with root privileges.

Try something like this, sudo -- useradd