📘 Week 5：結構與檔案操作

重點：資料組織、檔案讀寫
練習:設計資料結構

Day 1：結構定義與使用

#include <stdio.h>

struct Student {
  char name[20];
  int score;
};

int main() {
  struct Student s = {"會安", 95};
  printf("姓名：%s，分數：%d\n", s.name, s.score);
  return 0;
}
#include <stdio.h>

struct Point {
  int x;
  int y;
};

int main() {
  struct Point p;
  p.x = 3;
  p.y = 4;
  printf("座標：( %d, %d )\n", p.x, p.y);
  return 0;
}
#include <stdio.h>

struct Book {
  char title[30];
  int pages;
};

int main() {
  struct Book b = {"C語言入門", 256};
  printf("書名：%s，頁數：%d\n", b.title, b.pages);
  return 0;
}
#include <stdio.h>

struct Product {
  char name[20];
  float price;
};

int main() {
  struct Product p = {"滑鼠", 499.0};
  printf("商品：%s，價格：%.1f 元\n", p.name, p.price);
  return 0;
}

Day 2：結構陣列與迴圈

#include <stdio.h>

struct Student {
  char name[20];
  int score;
};

int main() {
  struct Student list[2] = {
    {"小明", 80},
    {"小華", 90}
  };

  for (int i = 0; i < 2; i++) {
    printf("%s 的分數是 %d\n", list[i].name, list[i].score);
  }
  return 0;
}
#include <stdio.h>

struct Point {
  int x, y;
};

int main() {
  struct Point points[3] = {{1,2}, {3,4}, {5,6}};
  for (int i = 0; i < 3; i++) {
    printf("點 %d：(%d,%d)\n", i, points[i].x, points[i].y);
  }
  return 0;
}
#include <stdio.h>

struct Product {
  char name[20];
  float price;
};

int main() {
  struct Product items[2] = {
    {"鍵盤", 799.0},
    {"耳機", 1299.0}
  };

  for (int i = 0; i < 2; i++) {
    printf("%s：%.1f 元\n", items[i].name, items[i].price);
  }
  return 0;
}
#include <stdio.h>

struct Book {
  char title[30];
  int pages;
};

int main() {
  struct Book books[2];
  for (int i = 0; i < 2; i++) {
    printf("請輸入書名與頁數：");
    scanf("%s %d", books[i].title, &books[i].pages);
  }

  for (int i = 0; i < 2; i++) {
    printf("書名：%s，頁數：%d\n", books[i].title, books[i].pages);
  }
  return 0;
}

Day 3：檔案寫入（fprintf）

#include <stdio.h>

int main() {
  FILE *fp = fopen("output.txt", "w");
  fprintf(fp, "Hello, C 語言！\n");
  fprintf(fp, "這是檔案寫入範例。\n");
  fclose(fp);
  return 0;
}
#include <stdio.h>

int main() {
  FILE *fp = fopen("scores.txt", "w");
  int score = 95;
  fprintf(fp, "分數：%d\n", score);
  fclose(fp);
  return 0;
}
#include <stdio.h>

int main() {
  FILE *fp = fopen("data.txt", "w");
  for (int i = 1; i <= 3; i++) {
    fprintf(fp, "第 %d 筆資料\n", i);
  }
  fclose(fp);
  return 0;
}
#include <stdio.h>

int main() {
  FILE *fp = fopen("info.txt", "w");
  char name[] = "會安";
  int age = 30;
  fprintf(fp, "姓名：%s\n年齡：%d\n", name, age);
  fclose(fp);
  return 0;
}

Day 4：檔案讀取（fscanf）

#include <stdio.h>

int main() {
  FILE *fp = fopen("output.txt", "r");
  char line[50];
  fgets(line, sizeof(line), fp);
  printf("讀到：%s", line);
  fclose(fp);
  return 0;
}
#include <stdio.h>

int main() {
  FILE *fp = fopen("scores.txt", "r");
  int score;
  fscanf(fp, "分數：%d", &score);
  printf("讀取分數：%d\n", score);
  fclose(fp);
  return 0;
}
#include <stdio.h>

int main() {
  FILE *fp = fopen("info.txt", "r");
  char name[20];
  int age;
  fscanf(fp, "姓名：%s\n年齡：%d", name, &age);
  printf("姓名：%s，年齡：%d\n", name, age);
  fclose(fp);
  return 0;
}
#include <stdio.h>

int main() {
  FILE *fp = fopen("data.txt", "r");
  char line[30];
  while (fgets(line, sizeof(line), fp)) {
    printf("讀取：%s", line);
  }
  fclose(fp);
  return 0;
}

Day 5：結構與檔案整合

#include <stdio.h>

struct Student {
  char name[20];
  int score;
};

int main() {
  struct Student s = {"會安", 100};
  FILE *fp = fopen("student.txt", "w");
  fprintf(fp, "%s %d\n", s.name, s.score);
  fclose(fp);
  return 0;
}
#include <stdio.h>

struct Student {
  char name[20];
  int score;
};

int main() {
  struct Student s;
  FILE *fp = fopen("student.txt", "r");
  fscanf(fp, "%s %d", s.name, &s.score);
  printf("姓名：%s，分數：%d\n", s.name, s.score);
  fclose(fp);
  return 0;
}
#include <stdio.h>

struct Product {
  char name[20];
  float price;
};

int main() {
  struct Product p = {"滑鼠", 499.0};
  FILE *fp = fopen("product.txt", "w");
  fprintf(fp, "%s %.2f\n", p.name, p.price);
  fclose(fp);
  return 0;
}
#include <stdio.h>

struct Product {
  char name[20];
  float price;
};

int main() {
  struct Product p;
  FILE *fp = fopen("product.txt", "r");
  fscanf(fp, "%s %f", p.name, &p.price);
  printf("商品：%s，價格：%.2f\n", p.name, p.price);
  fclose(fp);
  return 0;
}

Day 6：檔案開啟檢查與錯誤處理

#include <stdio.h>

int main() {
  FILE *fp = fopen("missing.txt", "r");
  if (fp == NULL) {
    printf("檔案開啟失敗！\n");
    return 1;
  }
  fclose(fp);
  return 0;
}
#include <stdio.h>

int main() {
  FILE *fp = fopen("readonly.txt", "w");
  if (!fp) {
    printf("無法寫入檔案。\n");
    return 1;
  }
  fprintf(fp, "測試寫入\n");
  fclose(fp);
  return 0;
}
#include <stdio.h>

void writeLog(const char *msg) {
  FILE *fp = fopen("log.txt", "a");
  if (fp == NULL) {
    printf("無法開啟 log.txt\n");
    return;
  }
  fprintf(fp, "%s\n", msg);
  fclose(fp);
}

int main() {
  writeLog("程式啟動成功");
  return 0;
}

Day 7：綜合資料結構設計與檔案儲存

#include <stdio.h>

struct Student {
  char name[20];
  int math;
  int english;
};

int main() {
  struct Student s = {"會安", 90, 85};
  FILE *fp = fopen("report.txt", "w");
  if (fp != NULL) {
    fprintf(fp, "%s %d %d\n", s.name, s.math, s.english);
    fclose(fp);
  }
  return 0;
}
#include <stdio.h>

struct Product {
  char name[20];
  float price;
  int stock;
};

int main() {
  struct Product p = {"滑鼠", 499.0, 20};
  FILE *fp = fopen("inventory.txt", "w");
  if (fp) {
    fprintf(fp, "%s %.2f %d\n", p.name, p.price, p.stock);
    fclose(fp);
  }
  return 0;
}
#include <stdio.h>

struct Book {
  char title[30];
  int pages;
};

int main() {
  struct Book books[2] = {
    {"C語言入門", 256},
    {"資料結構", 320}
  };

  FILE *fp = fopen("books.txt", "w");
  for (int i = 0; i < 2; i++) {
    fprintf(fp, "%s %d\n", books[i].title, books[i].pages);
  }
  fclose(fp);
  return 0;
}
#include <stdio.h>

struct Record {
  int id;
  char status[10];
};

int main() {
  struct Record r = {101, "完成"};
  FILE *fp = fopen("status.txt", "w");
  if (fp != NULL) {
    fprintf(fp, "ID:%d 狀態:%s\n", r.id, r.status);
    fclose(fp);
  }
  return 0;
}