Error installing

[elmerehbi]

Hello. Thanks for the nice idea. I was searching for something like this when I landed on your code. Unfortunately I can't seem t install it. Here's the output from running g++ main.cpp -o deskchange

main.cpp:16:25: error: ‘rawtime’ was not declared in this scope
   timeinfo = localtime(&rawtime);
                         ^
main.cpp:21:30: error: ‘atoi’ was not declared in this scope
   int time = atoi(str.c_str());
                              ^
main.cpp:25:50: error: ‘system’ was not declared in this scope
      system("feh --bg-scale ~/Pictures/night.jpg");
                                                  ^
main.cpp:28:50: error: ‘system’ was not declared in this scope
      system("feh --bg-scale ~/Pictures/night.jpg");
                                                  ^
main.cpp:31:49: error: ‘system’ was not declared in this scope
      system("feh --bg-scale ~/Pictures/day.jpeg");

PS: I do have feh installed.