error: ‘system’ was not declared in this scope | g++

error: ‘system’ was not declared in this scope

we need

#include <cstdlib>

error: ‘stdin’ was not declared in this scope | error: ‘fflush’ was not declared in this scope

error: ‘fflush’ was not declared in this scope

error: ‘stdin’ was not declared in this scope

we need

include <cstdio>

when we are migrating source code from windows on linux machine g++ prints the following errors

error: ‘strlen’ was not declared in this scope

error: ‘strcpy’ was not declared in this scope

we have to add #include <cstring>

now, strlen() and strcpy() will work correctly