C - 小さなツールの作成 - 1つのことだけをうまくやる(csvデータの読み込み、JSON形式の出力)

Head First C
原著

開発環境

• OS: macOS High Sierra - Apple
• Text Editor: Emacs
• コンパイラー: LLVM/Clang, GCC(gcc)
• プログラミング言語: C

Head First C ―頭とからだで覚えるCの基本 (David Griffiths (著)、Dawn Griffiths (著)、中田 秀基 (監修)、木下 哲也 (翻訳)、オライリージャパン)の3章(小さなツールの作成 - 1つのことだけをうまくやる)、ポケットコード(p. 105)を取り組んでみる。

ポケットコード(p. 105)

Makefile

CC = cc

all: sample run

sample: sample.c
 $(CC) sample.c -o sample

run: sample gpsdata.csv
 ./sample < gpsdata.csv

コード

#include <stdbool.h>
#include <stdio.h>

int main() {
  float latitude;
  float longitude;
  char info[80];
  int started = false;

  puts("data=[");
  while (scanf("%f,%f,%79[^\n]", &latitude, &longitude, info) == 3) {
    if (started) {
      puts(",");
    } else {
      started = true;
    }
    printf("{latitude: %f, longitude: %f, info: %s}", latitude, longitude,
           info);
  }
  puts("\n]");
}

入出力結果(Terminal)

$ make
cc sample.c -o sample
./sample < gpsdata.csv
data=[
{latitude: 42.363400, longitude: -71.098465, info: Speed = 21},
{latitude: 42.363327, longitude: -71.097588, info: Speed = 23},
{latitude: 42.363255, longitude: -71.096710, info: Speed = 17},
{latitude: 42.363182, longitude: -71.095833, info: Speed = 22},
{latitude: 42.363110, longitude: -71.094955, info: Speed = 14},
{latitude: 42.363037, longitude: -71.094078, info: Speed = 16},
{latitude: 42.362965, longitude: -71.093201, info: Speed = 18},
{latitude: 42.362892, longitude: -71.092323, info: Speed = 22},
{latitude: 42.362820, longitude: -71.091446, info: Speed = 17},
{latitude: 42.362747, longitude: -71.090569, info: Speed = 23},
{latitude: 42.362675, longitude: -71.089691, info: Speed = 14},
{latitude: 42.362602, longitude: -71.088814, info: Speed = 19},
{latitude: 42.362530, longitude: -71.087936, info: Speed = 16},
{latitude: 42.362457, longitude: -71.087059, info: Speed = 16},
{latitude: 42.362385, longitude: -71.086182, info: Speed = 21}
]
$