View Compilation Error

0_0_40071166_7451.cpp: In function 'void sortmsg(char*)':
0_0_40071166_7451.cpp:17:26: error: 'atoi' was not declared in this scope
   17 |             int nparse = atoi(source);
      |                          ^~~~
0_0_40071166_7451.cpp:28:30: error: 'atoi' was not declared in this scope
   28 |             int nparselast = atoi(source);
      |                              ^~~~