string - find_if 在字符串数组上

Question

我根据第一个字母从数组中查找所有字符串:

#include<iostream>
#include<algorithm>
#include<string>

int main(){

const std::string strArray[] =  {"an","blau","Bo","Boot","bos","da","Fee","fern","Fest","fort","je","jemand","mir","Mix",
                      "Mixer","Name","neu","od","Ort","so","Tor","Torf","Wasser"};

std::string value = "JNQ";
for_each(value.begin(), value.end(), [strArray](char c){
                  std::string const * iterator = find_if(strArray, strArray+23, [c](std::string str){
                                                    return toupper(str[0]) == c;
                                                 });
                  std::cout<<*iterator<<'\n';
          });

 return 0;
}

我得到这个输出:

je
Name
an

为什么显示'an'？我在 Ubuntu 上使用 g++ 4.5。

Answer 1

你的代码的问题是你没有检查 iterator 对数组的 end，在此行之前:

std::cout<<*iterator<<'\n';

实际上应该是这样的:

if (iterator != (strArray+23))  //print only if iterator != end
     std::cout<<*iterator<<'\n';

看到这个。它现在可以工作了。

• http://www.ideone.com/vyqlR

它不再打印"an"。 :-)