Question

Hello获取字符串的最后N个字符需要帮助：有这样的一行：

PutPixel(x + N, y + N, 0, 0, 0); // N = 1 - 1000

并希望得到最后9个符号，其中＆＃34; 0,0,0）;＆＃34; ，我有50k行的那些，每行有不同的数字，我想找到每一行0,0,0）;在最后并从数组中删除它，首先我必须找到它们我已经尝试了line[N].substr(0,-9);但是这样做不起作用，我也试过了line[N].find("0, 0, 0);");但这只是游戏我的长期谎言＆＃34; 4294967295＆＃34;

完整代码：

const string file = "putpixel.txt";
const int maxlines = 60000;
int main()
{
    string lines[maxlines];
    fileRead(file,lines);
    deleteBlack(lines);
    cout << lines[0].find("0, 0, 0);");
    return 0;
}

void fileRead(const string fn,string line[]){
    int index = 0;
    ifstream fin(fn.c_str());
    while(!fin.eof()){
        getline(fin,line[index],';');
        index++;
    }
    fin.close();
}

Answer 1

此代码从文件加载文本并搜索

" 0, 0, 0"并使用

替换为" "

searchresult = stringFile.find(" 0, 0, 0")和

substr( searchresult + search_string.length() , stringFile.length() )

它会一直这样做，直到searchresult = -1。如果是，它会将更改的结果写回文件。

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


int main(){

    int searchresult=1;
    ifstream inFile;

    // load file into string
    inFile.open("putpixel.txt"); 
    stringstream strStream;
    strStream << inFile.rdbuf(); 
    string stringFile = strStream.str(); 
    inFile.close();

    cout<<"\nBefore replace \n";
    cout<<""<<stringFile<<" \n";


    // initialize search string and replace string
    string search_string = " 0, 0, 0";
    string replace_string = " ";


    // while searchresult is still greater than zero then keep searching
    while ( searchresult > 0 ){

        searchresult = stringFile.find(search_string);

        // if searchresult is greater than zero then keep doing this
        if(searchresult >= 0){
             string tmpstring = stringFile.substr(0,searchresult);
             tmpstring += replace_string;
             tmpstring += stringFile.substr(searchresult+search_string.length(), stringFile.length());
             stringFile = tmpstring;
        }

    }
    // update file after removing
    ofstream outFile("putpixel.txt");
    outFile << stringFile;
    outFile.close();

    cout<<"\nAfter replace \n";
    cout<<""<<stringFile<<" \n";

cout<<"\nPress ANY key to close.\n\n";
cin.ignore(); cin.get();
return 0;
}

putpixel.txt之前的输出：

PutPixel(x + N, y + N, 0, 0, 0);
PutPixel(x + N, y + N, 0, 0, 0);
PutPixel(x + N, y + N, 0, 0, 0);
PutPixel(x + N, y + N, 0, 0, 0);

putpixel.txt之后的输出：

PutPixel(x + N, y + N, );
PutPixel(x + N, y + N, );
PutPixel(x + N, y + N, );
PutPixel(x + N, y + N, );

获取字符串的最后9个字符

1 个答案: