如何从文件中获取整数并将它们放入 int 向量中？

Question

我正在尝试获取一个文本文件并获取文件内的整数并将它们传输到一个可以读入不同函数的向量中。

这是我到目前为止所拥有的：

int main(int argc, char *argv[] )
{
vector<int> buff;
argv[1] = "input_24_0.txt";

if (argc < 2)
{
    std::cout << "usage: " << argv[0] << " <filename>\n";
    return 2;
}
std::ifstream fin(argv[1]);
if (fin)
{
    std::stringstream ss;
    // this copies the entire contents of the file into the string stream
    ss << fin.rdbuf();
    // get the string out of the string stream
    std::string contents = ss.str();
    std::cout << contents;
    // construct the vector from the string.
    std::vector<int> buff(contents.begin(), contents.end());
}
else 
{
    std::cout << "Couldn't open " << argv[1] << "\n";
    return 1;
}

clock_t t1, t2, t3, t4;

int maxSum;

t1 = clock();
maxSum = maxSubSum1(buff);
cout << "MaxSubSum1 is " <<  maxSum << endl;
cout << double( clock() - t1 )
/ (double)CLOCKS_PER_SEC<< " seconds." << endl;
t1 = clock() - t1;

t2 = clock();
maxSum = maxSubSum2( buff );
cout << "MaxSubSum2 is " <<  maxSum << endl;
cout << double( clock() - t2)
/ (double)CLOCKS_PER_SEC<< " seconds." << endl;
t2 = clock() - t2;

t3 = clock();
maxSum = maxSubSum3(buff );
cout << "MaxSubSum3 is " <<  maxSum << endl;
cout << double( clock() - t3 )
/ (double)CLOCKS_PER_SEC<< " seconds." << endl;
t3 = clock() - t3;

t4 = clock();
maxSum = maxSubSum4( buff );
cout << "MaxSubSum4 is " <<  maxSum << endl;
cout << double( clock() - t4 )
/ (double)CLOCKS_PER_SEC<< " seconds." << endl;
t4 = clock() - t4;

system("pause");

return 0;
 }

Answer 1

如果文件中的数字由空格分隔，您可以执行以下操作：

 std::ifstream iStream;
 iStream.open("filename.ext");
 int tempVariable;

 if (iStream) {
   while (iStream >> tempVariable) {
      // Any routines to check the value of the number if necessary
      vector.push_back(tempVariable);
   }
   iStream.close();
 }
 else
   // Error routine

如果数字不由空格分隔，您可以使用字符串流方法，并循环遍历流，将每个 char 转换为它是十进制值。