c++ - 函数中的 vector - 如何返回

Question

我有一个函数应该逐行读取文件，当一行不以'>'或''开头时读取停止。它应该将行存储在 vector 中并返回它。
这是代码:

    #include <cstdlib>
    #include <iostream>
    #include <string>
    #include <stdio.h>
    #include <fstream>
    #include <vector>

    using namespace std;

    string getseq(char * db_file) // gets sequences from file
            {
                string seqdb;
                vector<string> seqs;
                ifstream ifs(db_file);
                string line;

                //vector<char> seqs[size/3];

                while(ifs.good())
                {
                    getline(ifs, seqdb);
                    if (seqdb[0] != '>' & seqdb[0]!=' ')
                    {
                        seqs.push_back(seqdb);
                    }
                }

            ifs.close();
            //return seqs;

            //return seqs;
            }

    int main(int argc, char * argv[1])
    {
        cout << "Sequences: \n" << getseq(argv[1]) << endl;
        return 0;
    }

编译器 (g++) 返回:

    fasta_parser.cpp: In function ‘std::string getseq(char*)’:
    fasta_parser.cpp:32: error: conversion from ‘std::vector<std::basic_string<char, `std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >’ to non-scalar type ‘std::string’ requested`

有人知道吗？

编辑:正如 Skurmendel 所问，由于内存安全违规，我正在添加整个代码

执行编译代码:

#include <cstdlib>
#include <iostream>
#include <string>
#include <stdio.h>
#include <fstream>
#include <vector>

using namespace std;

vector<string> getseq(char * db_file) // pobiera sekwencje z pliku
        {
            string seqdb;
            vector<string> seqs;
            ifstream ifs(db_file);
            string line;

            //vector<char> seqs[size/3];

            while(ifs.good())
            {
                getline(ifs, seqdb);
                if (seqdb[0] != '>' & seqdb[0]!=' ')
                {
                    seqs.push_back(seqdb);
                }
            }

        ifs.close();
        return seqs;
        }

int main(int argc, char * argv[1])
{
    vector<string> seqs;   // Holds our strings.
    getseq(argv[1]); // We don't return anything.

    // This is just a matter of taste, we create an alias for the vector<string> iterator type.
    typedef vector<string>::iterator string_iter;

    // Print prelude.
    cout << "Sekwencje: \n";

    // Loop till we hit the end of the vector.
    for (string_iter i = seqs.begin(); i != seqs.end(); i++)
    {
        cout << *i << " "; // Do processing, add endlines, commas here etc.
    }

    cout << endl;
}

Answer 1

如果我理解你的话，你的 getseq() 应该返回一个字符串 vector 。因此你应该改变

string getseq(char * db_file)

到

vector<string> getseq(char * db_file)

如果你想在 main() 上打印它，你应该循环执行。

int main() {
     vector<string> str_vec = getseq(argv[1]);
     for(vector<string>::iterator it = str_vec.begin(); it != str_vec.end(); it++) {
         cout << *it << endl;
     }
}