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12장. 수업코드

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2022/05/28 22:19

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C++

12장. 수업 코드

파일 입출력

#include <iostream>
#include <fstream>
using namespace std;

int main() {
  char name[10], dept[20];
  int sid;

  cout << "name: ";
  cin >> name;
  cout << "sid: ";
  cin >> sid;
  cout << "dept: ";
  cin >> dept;

  ofstream fout("student.txt");
  if(!fout) {
    // 열기 실패한 경우
    cout << "student.txt 파일을 열 수 없습니다." << endl;
    return 0;
  }
  
  fout << name << endl;
  fout << sid << endl;
  fout << dept << endl;

  cout << "파일 저장 완료" <<  endl;
  fout.close();
}
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cat student.txt

#include <iostream>
#include <fstream>
using namespace std;

int main() {
  ifstream fin;
  fin.open("student.txt");
  if (!fin) {
    cout << "Not open" << endl;
    return 0;
  }

  char name[10], dept[20];
  int sid;

  fin >> name;
  fin >> sid;
  fin >> dept;

  fin.close();
  cout << name << sid << dept << endl;
}
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#include <iostream>
#include <fstream>
using namespace std;

int main() {
  ifstream fin;
  string fname = "student.txt";
  fin.open(fname);
  if (!fin) {
    cout << "Not open" << endl;
    return 0;
  }

  char name[10], dept[20];
  int sid;

  fin >> name;
  fin >> sid;
  fin >> dept;

  fin.close();
  cout << name << sid << dept << endl;

  string fName = "/etc/passwd";

  ifstream fin2(fName);
  if (!fin2) {
    cout << "File Open Fail:" << fName << endl;
    return 0;
  }
  int count = 0;
  int c;
  while((c = fin2.get()) != EOF) {
    cout << (char)c;
    count++;
  }
  cout << "Read Byte Count:" << count << endl;
  fin2.close();

  fstream fout2(fname, ios::out | ios::trunc);
  if (!fout2) return 0;
  fstream fin3(fName, ios::in);

  while((c = fin3.get()) != EOF) {
    fout2.put(c);
  }
  fin3.close();
  fout2.close();


  ifstream fin4;
  fin4.open(fName);
  if (!fin3) return 0;
  string line;
  while (getline(fin4, line))
    cout << line << endl;
  fin3.close();
}
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단어 찾기

#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

void fileRead(vector<string>& v, ifstream &fin) {
  string line;
  while(getline(fin, line))
    v.push_back(line);

  cout << v.size() << "단어를 읽었습니다." << endl;
}

void search(vector<string>& v, string word) {
  int count = 0;
  for (auto it = v.begin(); it != v.end(); it++) {
    int index = (*it).find(word);
    if(index != -1) {
      cout << *it << endl;
      count++;
    }
  }
  cout << "총 " << count << "개의 단어를 찾았습니다." << endl;
}

int main() {
  string wordFileName = "words.txt";
  ifstream fin(wordFileName);
  if(!fin) {
    cout << "파일 읽기 오류" << endl;
    return 0;
  }
  vector<string> v;
  fileRead(v, fin);
  fin.close();

  while(true) {
    cout << "검색할 단어:";
    string word;
    getline(cin, word);
    if(word == "exit") break;
    search(v, word);
    
  }
  cout << "종료!" << endl;
}
C++
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