C++操作文件进行读取、删除、修改指定行
代码如下:
/******************************************************** Copyright (C), 2016-2018, FileName: main Author: woniu201 Created: 2018/08/31 Description: 文件操作:读取指定行,删除指定行,修改指定行 ********************************************************/ #include <iostream> #include <fstream> #include <string> using namespace std; /************************************ @ Brief: 读取指定行数据 @ Author: woniu201 @ Created: 2018/08/31 @ Return: ************************************/ void ReadLineData(char* fileName, int lineNum, char* data) { ifstream in; in.open(fileName); int line = 1; while (in.getline(data, 1024)) { if (lineNum == line) { break; } line ++ ; } in.close(); } /************************************ @ Brief: 字符串转string类型 @ Author: woniu201 @ Created: 2018/08/31 @ Return: ************************************/ string CharToStr(char * contentChar) { string tempStr; for (int i=0;contentChar[i]!='\0';i++) { tempStr+=contentChar[i]; } return tempStr; } /************************************ @ Brief: 删除指定行 @ Author: woniu201 @ Created: 2018/08/31 @ Return: ************************************/ void DelLineData(char* fileName, int lineNum) { ifstream in; in.open(fileName); string strFileData = ""; int line = 1; char lineData[1024] = {0}; while(in.getline(lineData, sizeof(lineData))) { if (line == lineNum) { strFileData += "\n"; } else { strFileData += CharToStr(lineData); strFileData += "\n"; } line++; } in.close(); //写入文件 ofstream out; out.open(fileName); out.flush(); out<<strFileData; out.close(); } /************************************ @ Brief: 修改行数据 @ Author: woniu201 @ Created: 2018/08/31 @ Return: ************************************/ void ModifyLineData(char* fileName, int lineNum, char* lineData) { ifstream in; in.open(fileName); string strFileData = ""; int line = 1; char tmpLineData[1024] = {0}; while(in.getline(tmpLineData, sizeof(tmpLineData))) { if (line == lineNum) { strFileData += CharToStr(lineData); strFileData += "\n"; } else { strFileData += CharToStr(tmpLineData); strFileData += "\n"; } line++; } in.close(); //写入文件 ofstream out; out.open(fileName); out.flush(); out<<strFileData; out.close(); } int main() { char lineData[1024] = {0}; ReadLineData("D:\\project\\cpp\\2010\\jsondemo\\jsondemo\\1.json", 21, lineData); cout << lineData << endl; DelLineData("D:\\project\\cpp\\2010\\jsondemo\\jsondemo\\1.json", 10); ModifyLineData("D:\\project\\cpp\\2010\\jsondemo\\jsondemo\\1.json", 10, "aaaaaaaaaaaaaa"); getchar(); }
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