domiyanyue

## hello.cpp
#include <iostream>

int main(){
  std::cout << "Hello World";
  return 0;
}

## compile_1.sh
g++ hello.cpp -o hello
./hello
Hello World

## warning_example.cpp
int main(){
    int a = 1;
    return 0;
}

## compile_warning.txt
cpp_tutorial# g++ warning_example.cpp -Wall -o a
warning_example.cpp: In function ‘int main()’:
warning_example.cpp:2:9: warning: unused variable ‘a’ [-Wunused-variable]
     int a = 1;
         ^

## warning_example_uninitialized.cpp

int main(){
    int array[100];
    return array[1];
}

## c++_waring_as_error.txt
cpp_tutorial# g++ warning_example.cpp  -Wuninitialized -o a -Werror
warning_example.cpp: In function ‘int main()’:
warning_example.cpp:4:19: error: ‘array[1]’ is used uninitialized in this function [-Werror=uninitialized]
     return array[1];
                   ^
cc1plus: all warnings being treated as errors

## macro_compile.cpp
#include <iostream>
#ifndef SIZE_ARRAY
#define SIZE_ARRAY 4
#endif

int main(){
    int array[SIZE_ARRAY] = {0};
    std::cout << "num of elements: " << sizeof(array)/sizeof(array[0]) << "\n";
    return 0;
}

## main.cpp
#include "vars.h"

int main(){
  return 0;
}

## main.cpp
int a = 1;

int foo(){
  return 2;
}

int main(){
  return 0;
}

## 1_run.txt
g++ -E example.cpp -o _preprocess.out
	#include <iostream>

	int main(){
	std::cout << "Hello World";
	return 0;
	}
	cpp_tutorial# g++ warning_example.cpp -Wall -o a
	warning_example.cpp: In function ‘int main()’:
	warning_example.cpp:2:9: warning: unused variable ‘a’ [-Wunused-variable]
	int a = 1;
	^
	cpp_tutorial# g++ warning_example.cpp -Wuninitialized -o a -Werror
	warning_example.cpp: In function ‘int main()’:
	warning_example.cpp:4:19: error: ‘array[1]’ is used uninitialized in this function [-Werror=uninitialized]
	return array[1];
	^
	cc1plus: all warnings being treated as errors
	#include <iostream>
	#ifndef SIZE_ARRAY
	#define SIZE_ARRAY 4
	#endif

	int main(){
	int array[SIZE_ARRAY] = {0};
	std::cout << "num of elements: " << sizeof(array)/sizeof(array[0]) << "\n";
	return 0;
	}