c++ - 从文件中的特定位置查找文件中最后一次出现的字符串

Question

我想从一个固定的特定位置(a分隔符)在同一个文件中。我找到了所有事件，但如何从特定位置打印最后一次/最后一次事件？

这是我的代码:

#include <iostream>
#include <string>
#include <fstream>

using namespace std;

int main()
{
    ifstream file;
    string line;
    char* str = "A-B";
    file.open("test.txt");
    unsigned int currline = 0;
    while(getline(file, line)) {
        currline++;
        if (line.find(str, 0) != string::npos) {
            cout << "found your search term: " << str << " at the " <<"line no.: " << currline << endl;
        }
    }
    return 0;
}

这是我的文本文件的示例数据:

A,A-B,127.0.0.1
B,B-C,127.0.0.1
# // *From this point I have to search downwards only!*
A-B_1,01-01-15,2,2,L
A-B_2,01-02-15,2,0,L
B-C_1,02-01-16,4,0,L

Answer 1

在每次迭代时将找到的文本分配给一个变量将覆盖变量内容并在循环结束后打印它只会打印最后一次出现:

应该这样做:

#include <iostream>
#include <string>
#include <fstream>

using namespace std;

int main()
{
    ifstream file;
    string line;
    string found = "Nothing found";
    char* str = "A-B";
    file.open("test.txt");
    unsigned int currline = 0;
    while(getline(file, line)) {
        currline++;
        if (line.find(str, 0) != string::npos) {
            found = line;
        }
    }
    cout << found << endl;
    return 0;
}