C++ 使用 ifstream 按行读取文件内容

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#include <fstream>
std::ifstream infile("thefile.txt");

int a, b;
while (infile >> a >> b)
{
    // process pair (a,b)
}

#include <sstream>
#include <string>

std::string line;
while (std::getline(infile, line))
{
    std::istringstream iss(line);
    int a, b;
    if (!(iss >> a >> b)) { break; }

    // process pair (a,b)
}