linux下cout的问题，很奇怪的现象

[Pory]

代码如下：

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <map>
#include <vector>
#include <fstream>
#include <string.h>
#define BUFMAXSIZE (1024*1024)

using namespace std;

void strToMap(std::string str, std::map<std::string, float> &featMap);
int main(void){
	vector<map<string,float> > feats;
	ifstream dataFileIn("lr.txt", ios::in);
	int k = 1;
	if (dataFileIn.fail())
	{
		std::cout << "error: data feat open failure\n";
	}
	char *buffer = (char*)malloc(BUFMAXSIZE * sizeof(char));
	while (!dataFileIn.eof())
	{
		memset(buffer, 0, BUFMAXSIZE);
		dataFileIn.getline(buffer, BUFMAXSIZE);
		map<string, float> temp;
		strToMap(buffer, temp);
		feats.push_back(temp);
	}
	while (k--)
	{
		for (map<string, float> feat : feats)
		{
            for(map<string,float>::iterator iter=feat.begin(); iter != feat.end(); iter++)
            {
                cout<<iter->first<<"\n";
            }
            cout<<"\n";
		}
	}

	free(buffer);
	dataFileIn.close();
    return 0;

}


void strToMap(std::string str, std::map<std::string, float> &featMap)
{
	const char *sep = ",";
	char *cbuff = new char[str.size() + 100];
	strncpy(cbuff, str.c_str(), str.size() + 1);
	char *p = nullptr;
	char *token = strtok_r(cbuff, sep, &p);
	while (token)
	{
		featMap.insert(std::pair<std::string, float>(token, 1.0));
		token = strtok_r(NULL, sep, &p);
	}
	delete cbuff;
	return;
}

其中输入文件lr.txt的内容为

T-L:195-34,T-L:196-55,T-L:197-20,T-L:198-29,C3:2675,C3:2675-C3:672
T-L:195-34,T-L:196-55,T-L:197-20,T-L:198-29,C3:2676,C3:2676-C3:672
T-L:195-34,T-L:196-55,T-L:197-20,T-L:198-29,C3:2675,C3:2675-C3:672

输出为
该结果正常。
但若将代码中 cout<<iter->first<<"\n"; 改为 cout<<iter->first<<",";
输出则为
明显少了2个分割的字符串，这是为什么呢？纠结了一下午。
当然如果lr.txt里文本如果每行最后都吧“,”带上，则不管怎么输出都能正常分割并显示子串，现在不明白是分割字符串的方式不安全还是cout不安全造成的。求大神指导
实验环境ubuntu64,c++至少支持c11，不过我的实验环境是c14