C++ 实用的小程序

１．　打开test_ids.txt　将里面的东西添加"1_",然后另存为test_ids_repaired.txt

#include <iostream>
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
using namespace std;
int main(){

    ifstream file;
    file.open("/home/wangxiao/Downloads/Link to ASPL---code/features/test_ids.txt");
    ofstream in("/home/wangxiao/Downloads/test_ids_repaired.txt");

    std::string line;
    std::string image_id;

    while(getline(file, line)){
        std::string add = "1_";
        line = add + line;

        image_id = line;
        in<<image_id<<endl;
    }
 }

 

 

 

 

2 : 编写一个程序，读入string和int的序列，将每个string和int存入一个pair中，pair保存在一个vector中．

 

＃include<iostream>
#include<fstream>
#include<utility>
#include<vector>
#include<string>
#include<algorithm>

using namespace std;
int main(int argc, char *argv[])
{
      ifstream in(argv[1]);
      if (!in) {
          cout<<”打开输入文件失败！”<<endl;
          exit(1);
      }

vector<pair<string, int>> data;
string s;
int v;
while (in>>s && in>>v)
     data.push_back(pair<string, int>(s, v));
  // data.push_back({s, v});  列表初始化的方式；
  // data.push_back(make_pair(s, v));　或者使用 make_pair ;

for (const auto &d : data)
     cout<<d.first<<” ---> ”<<d.second<<endl;

   return 0;
}

3. 打开test_ids.txt　将里面的东西添加"i_",然后另存为test_ids_repaired.txt  从１～88种　．．．

#include <iostream>
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
using namespace std;

int main(){

    ifstream file;
    file.open("/home/wangxiao/Downloads/ASPL_matlabFiles/test_ids.txt");
    ofstream in("/home/wangxiao/Downloads/ASPL_matlabFiles/outPut_test_ids.txt");

    std::string line;
    std::string image_id;


for (int i=1;i<89;i++){

   for (int j=1;j<52;j++){

       getline(file, line);
       stringstream ss;
       string s;
       ss << i;
       ss >> s;
       string add = s + "_";
       image_id = add + line;
       in<<image_id<<endl;

   }
}
 }