Table of contents
1. Function description
| Function name | illustrate | |
|---|---|---|
| 1 | CompareFileFileds() | Read the txt file by character or line, and then use string::find()the function to find the specified field. If it is found, it will return 0, if it is not found, it will return -1. |
2. Code
Method 1. Use the "<<" operator
Description: Reading characters will stop when encountering a space.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int CompareFileFileds(string filePath, string compareFileds)
{
fstream fs;
fs.open(filePath);
if (fs.fail())
{
fs.close();
cout << "fstream fail!" << endl;
return -1;
}
string fileString;
while (fs >> fileString) //读取字符直到遇到空格
{
int index = fileString.find(compareFileds, 1);
if (index > 0)
{
cout << "compare fileds index : " << index << endl;
return 0;
}
}
cout << "not find compareFileds!" << endl;
return -1;
}
int main()
{
string filePath = "C:\\Users\\ad\\Desktop\\file1.txt";
string compareFileds = "ABC";
int ret = CompareFileFileds(filePath, compareFileds);
if (ret == 0)
{
cout << "Compare sucess!" << endl;
}
else
{
cout << "Compare fail!" << endl;
}
system("pause");
return 0;
}
Method 2. Use string::getline()
Note: Read by line, even if there are spaces in a line, all can be read.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int CompareFileFileds(string filePath, string compareFileds)
{
fstream fs;
fs.open(filePath);
if (fs.fail())
{
fs.close();
cout << "fstream fail!" << endl;
return -1;
}
string fileString;
while (getline(fs,fileString)) //读取一行
{
int index = fileString.find(compareFileds, 1);
if (index > 0)
{
cout << "compare fileds index : " << index << endl;
return 0;
}
}
cout << "not find compareFileds!" << endl;
return -1;
}
int main()
{
string filePath = "C:\\Users\\ad\\Desktop\\file1.txt";
string compareFileds = "ABC";
int ret = CompareFileFileds(filePath, compareFileds);
if (ret == 0)
{
cout << "Compare sucess!" << endl;
}
else
{
cout << "Compare fail!" << endl;
}
system("pause");
return 0;
}
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