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使用ifstream和getline读取文件内容[c++]
转载:http://www.cnblogs.com/JCSU/articles/1190685.html
假设有一个叫 data.txt 的文件, 它包含以下内容:
Fry: One Jillion dollars.[Everyone gasps.]Auctioneer: Sir, that‘s not a number.数据读取, 测试 。
以下就是基于 data.txt 的数据读取操作:
#include <iostream>#include <fstream>#include <string>using namespace std;//输出空行void OutPutAnEmptyLine(){ cout<<"\n";}//读取方式: 逐词读取, 词之间用空格区分//read data from the file, Word By Word//when used in this manner, we‘ll get space-delimited bits of text from the file//but all of the whitespace that separated words (including newlines) was lost. void ReadDataFromFileWBW(){ ifstream fin("data.txt"); string s; while( fin >> s ) { cout << "Read from file: " << s << endl; }}//读取方式: 逐行读取, 将行读入字符数组, 行之间用回车换行区分//If we were interested in preserving whitespace, //we could read the file in Line-By-Line using the I/O getline() function.void ReadDataFromFileLBLIntoCharArray(){ ifstream fin("data.txt"); const int LINE_LENGTH = 100; char str[LINE_LENGTH]; while( fin.getline(str,LINE_LENGTH) ) { cout << "Read from file: " << str << endl; }}//读取方式: 逐行读取, 将行读入字符串, 行之间用回车换行区分//If you want to avoid reading into character arrays, //you can use the C++ string getline() function to read lines into stringsvoid ReadDataFromFileLBLIntoString(){ ifstream fin("data.txt"); string s; while( getline(fin,s) ) { cout << "Read from file: " << s << endl; }}//带错误检测的读取方式//Simply evaluating an I/O object in a boolean context will return false //if any errors have occurredvoid ReadDataWithErrChecking(){ string filename = "dataFUNNY.txt"; ifstream fin( filename.c_str()); if( !fin ) { cout << "Error opening " << filename << " for input" << endl; exit(-1); }}int main(){ ReadDataFromFileWBW(); //逐词读入字符串 OutPutAnEmptyLine(); //输出空行 ReadDataFromFileLBLIntoCharArray(); //逐词读入字符数组 OutPutAnEmptyLine(); //输出空行 ReadDataFromFileLBLIntoString(); //逐词读入字符串 OutPutAnEmptyLine(); //输出空行 ReadDataWithErrChecking(); //带检测的读取 return 0;}
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