没有匹配的 function 调用 'std::vector <std.. '< div><div id="text_translate"><p> 我正在解决的问题是：我必须采用<strong>T</strong>测试用例。 For each test case I have to take string as an input, then I need to arrange the input string as: <em>string at even position {double space} string at odd position</em> (example: <em>input</em> - StackOverflow, <em>output</em> - <strong>Sakvrlw</strong> <strong>tcOefo</strong> ). 我编写了以下代码，其中我为所有测试用例获取输入并将其存储在向量中。 然后我将 vector 的元素分配给另一个声明的 string s。</p><pre> #include &lt;cmath&gt; #include &lt;cstdio&gt; #include &lt;vector&gt; #include &lt;iostream&gt; #include &lt;algorithm&gt; #include &lt;string&gt; using namespace std; int main() { /* Enter your code here. Read input from STDIN. Print output to STDOUT */ int T,i; cout &lt;&lt; "Enter no. of test cases: "; cin &gt;&gt; T; vector&lt;string&gt; v; vector&lt;string&gt; odd; vector&lt;string&gt; even; string str; for(int i=0; i&lt;T; i++){ cin &gt;&gt; str; v.push_back(str); } string s; for(i=0; i&lt;v.size(); i++){ s = v.at(i); for(i=0; i&lt;s.size(); i++){ if(i==0){ even.push_back(s[i]); //*This is where I am getting error*. }else if(i==1){ odd.push_back(s[i]); }else{ if(i%2==0){ even.push_back(s[i]); }else{ odd.push_back(s[i]); } } } for(i=0; i&lt;even.size(); i++){ cout &lt;&lt; even.at(i); } cout &lt;&lt; " "; for(i=0; i&lt;odd.size(); i++){ cout &lt;&lt; odd.at(i); } cout &lt;&lt; endl; even.clear(); odd.clear(); s.clear(); } return 0; }</pre><p> 在编译上面的代码时，我得到"no matching error for call std::vector..." 。 <strong><em>我到底做错了什么？</em></strong></p></div></std..>

Question

The question I am solving states: I have to take T test cases. For each test case I have to take string as an input, then I need to arrange the input string as: string at even position {double space} string at odd position (example: input - StackOverflow, output - Sakvrlw tcOefo ). I've written the following code where I am taking input for all test cases and storing it in a vector. Then I am assigning the elements of vector to another declared string s.

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
     int T,i;
     cout << "Enter no. of test cases: ";
     cin >> T;

     vector<string> v;
     vector<string> odd;
     vector<string> even;
     string str;

     for(int i=0; i<T; i++){
        cin >> str;
        v.push_back(str);
     }


     string s;

     for(i=0; i<v.size(); i++){
        s = v.at(i);

        for(i=0; i<s.size(); i++){
            if(i==0){
                even.push_back(s[i]);  //*This is where I am getting error*.
            }else if(i==1){
                odd.push_back(s[i]);
            }else{
                if(i%2==0){
                    even.push_back(s[i]);
                }else{
                    odd.push_back(s[i]);
                }
            }
        }

        for(i=0; i<even.size(); i++){
            cout << even.at(i);
        }

        cout << "  ";

        for(i=0; i<odd.size(); i++){
            cout << odd.at(i);
        }

        cout << endl;

        even.clear();
        odd.clear();
        s.clear();
     }


     return 0;
}

While compiling the above code I'm getting "no matching error for call std::vector..." . What exactly am I doing wrong?

Answer 1

I am getting the following error when compiling your code:

main.cpp:34:36: error: no matching function for call to 'std::vector >::push_back(char&)' .

This happens because even is a vector<string> , and s[i] is a char . You are trying to insert a char into a vector of strings, and that is not possible, as they are different types.

If I understood your problem properly, even and odd must both be either vector<char> or string , not vector<string> .

Change the declarations to:

string odd;
string even;

This also allows you to replace the printing:

for(i=0; i<even.size(); i++) {
    cout << even.at(i);
}

With:

cout << even;

Answer 2

Welcome to Stack Overflow @Manish Jha,

So s[i] is a char

s is a std::string or an array of char s

The method must be push_back(std::string&) not push_back(std::char&)

The class template method std::vector::push_back(T&) is kind of "specialized" when you initialized your even/odd vector so, either append a std::string to std::vector<std::string> or a char to std::vector<char>

Otherwise, there is no maching for call the method std::vector<T>::push_back(T&)

Hope i answered correctly to your waitings, if there are any errors, please notify me.