通过在每个元素后添加逗号,将C++ Vector转换为CSV

Question

vector<string> v;
v.push_back("A");
v.push_back("B");
v.push_back("C");
v.push_back("D");

for (vector<int>::iterator it = v.begin(); it!=v.end(); ++it) {
//printout 
   cout << *it << endl;

}

我想在每个元素之后添加一个逗号,如下所示: A,B,C,D

我尝试过研究Google,但我只发现了CSV vector.

Answer 1

您可以在for循环中输出逗号:

for (vector<int>::iterator it = v.begin(); it!=v.end(); ++it) {
//printout 
   cout << *it << ", " << endl;
}

或者,您可以使用该copy算法.

std::copy(v.begin(), v.end(), std::ostream_iterator<char*>(std::cout, ", "));

Answer 2

循环方式:

for (vector<string>::iterator it = v.begin(); it != v.end(); ++it) {
   if (it != v.begin()) cout << ',';
   cout << *it;
}

"聪明"的方式:

#include <algorithm>
#include <iterator>

if (v.size() >= 2)
   copy(v.begin(), v.end()-1, ostream_iterator<string>(cout, ","));
if (v.size() >= 1)
   cout << v.back();