如何將字符串轉換爲浮點數組？

Question

你會如何轉換一個字符串，讓我們說： string Numbers = "0.3 5.7 9.8 6.2 0.54 6.3";成一個浮點數組，例如：float Numbers[6] = {0.3, 5.7, 9.8, 6.2, 0.54, 6.3};？

Answer 1

我會用數據結構和算法從std::：

#include <string> 
#include <vector> 
#include <algorithm> 
#include <iterator> 
#include <iostream> 
#include <cassert> 
#include <sstream> 

int main() { 
    std::string Numbers = "0.3 5.7 9.8 6.2 0.54 6.3"; 

    // If possible, always prefer std::vector to naked array 
    std::vector<float> v; 

    // Build an istream that holds the input string 
    std::istringstream iss(Numbers); 

    // Iterate over the istream, using >> to grab floats 
    // and push_back to store them in the vector 
    std::copy(std::istream_iterator<float>(iss), 
     std::istream_iterator<float>(), 
     std::back_inserter(v)); 

    // Put the result on standard out 
    std::copy(v.begin(), v.end(), 
     std::ostream_iterator<float>(std::cout, ", ")); 
    std::cout << "\n"; 
}