Question

编译此代码时，我在函数调用时遇到错误"Error: initialization with '{...}' expected for aggregate object"。我正在使用Visual Studio 11进行编译。

#include <iostream>
#include <string>
#include <array>
using namespace std;

typedef std::array<string, 5> string_t;
string_t centerString(std::array<string, 5> (&tempArray),unsigned short int length);
string_t evenString(std::array<string, 5> (&tempArray),unsigned short int length);

int main(){
    std::array<string, 5> aArray = {"a","aa","aaa","aaaa","aaaaa"};

    std::array<string, 5> evenStr[5] = evenString(aArray,5);
    std::array<string, 5> centerStr[5] = centerStr(aArray,5);
}


 string_t evenString(std::array<string, 5> (&srcArray),unsigned short int length){
     std::array<string, (sizeof(srcArray)/sizeof(srcArray[0]))> trgtArray= {};
     for(unsigned short int x = 0; x < (sizeof(srcArray)/sizeof(srcArray[0]));x++){
         trgtArray[x] = srcArray[x];
         for(unsigned short int y = 0; y < (length-trgtArray[x].length()); y++){
             trgtArray[x] += " ";
         }
     }

     return(trgtArray);
}

 string_t centerString(std::array<string, 5> (&srcArray),unsigned short int length){
     std::array<string, (sizeof(srcArray)/sizeof(srcArray[0]))> trgtArray= {};
     unsigned short int remainder;
     string spacer = "";
     for(unsigned short int x = 0; x < (sizeof(srcArray)/sizeof(srcArray[0]));x++){
         remainder = length - srcArray[x].length();
         if((remainder % 2) == 0){
            trgtArray[x] = srcArray[x];
            for(unsigned short int y = 0; y < (length-srcArray[x].length()); y++){
                trgtArray[x] += " ";
            }
         }else{
             for(unsigned short int z = 0; z < (remainder/2); z++){
                 spacer += " ";
             }
             trgtArray[x] = spacer + srcArray[x] + spacer + " ";
         }
     }

     return(trgtArray);
 }

Answer 1

您将在centerString

中返回临时参考

string_t& centerString(std::array<string, 5> (&tempArray),unsigned short int length);

centerStr是数组，不能用它作为函数

std::array<string, 5> centerStr = centerStr(aArray,5);

我猜你的意思是

std::array<string, 5> centerStr = centerString(aArray,5);

你可以尝试下面的示例函数，只需返回数组，RVO应该启动。

std::array<string,5> evenString(std::array<string, 5> (&srcArray), unsigned short length){
     std::array<string,5> trgtArray = {};
    //....
     return trgtArray;
}  

std::array<string, 5> evenStr = evenString(aArray,5);
std::array<string, 5> centerStr = centerString(aArray,5);

Answer 2

不要使用原生数组，他们会骇人听闻，这是他们吮吸的方式之一。基本上，这将要求阵列采取合理的行动，而不是。语言强制执行的错误基本上意味着他们无法完成您希望从任何其他数据类型中获得的大量内容，并且当您可以使用std::array时，他们真的不值得花时间使用 ~~baus~~ 理智的人。

使用std::array并感激甚至委员会接受C阵列的吮吸。

我有趣的是，请注意您确实包含<array>，但之后没有使用std::array。

c ++，“错误：初始化为'{...}'期望聚合对象”

2 个答案: