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· 6 min read
aweffr

Motiviation​

帮一位同学开始系统地学计算机, 考虑到CS61A/B/C路线对英文和找资料有比较高的要求, 遂为其转进国内优秀课程路线. 为了能够使用上配套的OJ, 先搞定一下C语言mac开发环境.

入门这块OJ很重要，毕竟, 想成为一名好程序员, 编程这门手艺活还是得6啊.

总体步骤​

  1. 安装XCode
  2. VS Code 安装插件
    1. C/C++ Extension Pack
    2. Code Runner
  3. 新建项目
    1. mkdir learning-c-programming && cd learning-c-programming && mkdir {.vscode,build}
  4. 使用VS Code打开目录, 新建以下文件
    1. tasks.json # 用于编译c++文件
    2. launch.json # 用于使用vscode自带的debug工具（左侧的小虫图标）
    3. c_cpp_properties.json # 用于使用vscode自带的代码提示工具如 IntelliSense
    4. settings.json # 添加 Code Runner 相关配置

Workspace 配置文件​

配置 tasks.json​

快捷键 Command+Shift+B, vscode会执行tasks.json中的任务.

文件内容如下:

{
    "version": "2.0.0",
    "tasks": [
        {
            "label": "C/C++: clang++ 生成活动文件",
            "type": "shell",
            "command": "clang",
            "args": [
                "-Wall",
                "-Wno-unused-variable",
                "-std=c++17",
                "-g",
                "${file}",
                "-o",
                "${workspaceFolder}/build/${fileBasenameNoExtension}"
            ],
            "options": {
                "cwd": "${workspaceFolder}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": "build"
        }
    ]
}

配置 c_cpp_properties.json​

c_cpp_properties.json 的作用是：代码提示、代码跳转等

{
    "configurations": [
        {
            "name": "Mac",
            "includePath": [
                "${workspaceFolder}/**",
                "/Library/Developer/CommandLineTools/usr/include",
                // 注意, clang的include文件位置需要根据实际安装结果修改
                "/Library/Developer/CommandLineTools/usr/lib/clang/12.0.5/include",
                "/usr/local/include"
            ],
            "defines": [],
            "macFrameworkPath": [
                "/System/Library/Frameworks",
                "/Library/Frameworks"
            ],
            "compilerPath": "/usr/bin/clang++",
            "cStandard": "c11",
            "cppStandard": "c++17",
            "intelliSenseMode": "clang-x64"
        }
    ],
    "version": 4
}

配置 launch.json​

launch.json是调用vscode debug功能的配置文件

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "clang++ - 生成和调试活动文件",
            "type": "cppdbg",
            "request": "launch",
            "program": "${workspaceFolder}/build/${fileBasenameNoExtension}",
            "args": [
                "args", "can", "be", "there"
            ],
            "stopAtEntry": false,
            "cwd": "${workspaceFolder}/build",
            "environment": [],
            "externalConsole": false,
            "MIMode": "lldb",
            "preLaunchTask": "C/C++: clang++ 生成活动文件"
        }
    ]
}

配置 settings.json​

配置 Code Runner 来快捷执行代码。

  • Control+Option+N 编译并执行代码
  • Control+Option+M 终止执行
{
    "files.associations": {
        "__bit_reference": "c",
        "__string": "c",
        "cstring": "c",
        "cstdio": "c"
    },
    "code-runner.executorMap": {
        "c": "cd $dir && clang -Wall -Wno-unused-variable -Wno-implicit-function-declaration -std=c11 $fileName -o $workspaceRoot/build/$fileNameWithoutExt && cd $workspaceRoot/build && ./$fileNameWithoutExt",
        "cpp": "cd $dir && clang++ -Wall -Wno-unused-variable -Wno-implicit-function-declaration -std=c++17 $fileName -o $workspaceRoot/build/$fileNameWithoutExt && cd $workspaceRoot/build && ./$fileNameWithoutExt"
    }
}

使用说明​

c程序示例 处理输入​

/**
 * @file bubble-sort.cpp
 * @author aweffr (aweffr@foxmail.com)
 * @brief 提交OJ模板, 演示: 1. 读数组数据 2. 按环境区分如何处理输入
 * @version 0.1
 * @date 2022-03-12
 */
#include <cstdio>
#include <cstdlib>
#include <cstring>

#define MAX_INPUT_SIZE 50000

#define __DEV__ 0
#define __DEV_FILE__ "/Users/aweffr/Developer/learning-c-programming/problem-set1/input.txt"

void swap(int *arr, int i, int j);

/**
 * @brief 根据 __DEV__ 决定是从编写的测试input文件还是OJ的stdin读取输入
 *
 * @return FILE*
 */
FILE *get_input()
{
  FILE *fptr = stdin;
  if (__DEV__)
  {
    printf("[DEBUG]Reading input from %s ...\n", __DEV_FILE__);
    fptr = fopen(__DEV_FILE__, "r");
    if (fptr == NULL)
    {
      printf("Open File Error!");
      exit(1);
    }
  }
  return fptr;
}

int main(int argc, char *argv[])
{
  int N = 0;

  FILE *fptr = get_input();

  fscanf(fptr, "%d\n", &N);

  int input_arr[MAX_INPUT_SIZE];
  memset(input_arr, 0, MAX_INPUT_SIZE);

  for (int i = 0; i < N; i++)
  {
    fscanf(fptr, "%d\n", &input_arr[i]);
  }

  for (int i = 0; i < N; i++)
  {
    for (int j = 0; j < N - 1; j++)
    {
      if (input_arr[j] > input_arr[j + 1])
      {
        swap(input_arr, j, j + 1);
      }
    }
  }

  printf("sorted result: ");
  for (int i = 0; i < N; i++)
  {
    const char *fmt = (i == 0) ? " %d" : ", %d";
    printf(fmt, input_arr[i]);
  }
  printf("\n");

  return 0;
}

void swap(int *arr, int i, int j)
{
  int tmp = arr[i];
  arr[i] = arr[j];
  arr[j] = tmp;
}

Code Runner 执行效果:

[Running] cd "/Users/aweffr/Developer/learning-c-programming/problem-set1/" && clang++ -Wall -Wno-unused-variable -Wno-implicit-function-declaration -std=c++17 bubble-sort.cpp -o /Users/aweffr/Developer/learning-c-programming/build/bubble-sort && cd /Users/aweffr/Developer/learning-c-programming/build && ./bubble-sort
[DEBUG]Reading input from /Users/aweffr/Developer/learning-c-programming/problem-set1/input.txt ...
sorted result:  1, 2, 3, 4, 8, 11, 111, 123, 12312, 12313

[Done] exited with code=0 in 2.958 seconds

参考文档​

  1. segmentfault: mac vscode c++ 环境配置及异常的语法提示
  2. VS Code 官方文档: Using Clang in Visual Studio Code
  3. VS Code变量参考手册
  4. Clang 命令行手册
  5. CMU 15-123 C & Unix S11
  6. CMU 15-123 C & Unix N09