如何将文本追加到C++文本文件中？

Question

如何将文本追加到C++中的文本文件？创建新的if不存在并追加（如果存在）。

Answer 1

#include <fstream> 

int main() { 
    std::ofstream outfile; 

    outfile.open("test.txt", std::ios_base::app); 
    outfile << "Data"; 
    return 0; 
} 

Answer 2

#include <fstream> 
#include <iostream> 

FILE * pFileTXT; 
int counter 

int main() 
{ 
pFileTXT = fopen ("aTextFile.txt","a");// use "a" for append, "w" to overwrite, previous content will be deleted 

for(counter=0;counter<9;counter++) 
fprintf (pFileTXT, "%c", characterarray[counter]);// character array to file 

fprintf(pFileTXT,"\n");// newline 

for(counter=0;counter<9;counter++) 
fprintf (pFileTXT, "%d", digitarray[counter]); // numerical to file 

fprintf(pFileTXT,"A Sentence");     // String to file 

fprintf (pFileXML,"%.2x",character);    // Printing hex value, 0x31 if character= 1 

fclose (pFileTXT); // must close after opening 

return 0; 

} 

Answer 3

我用这个代码。它确保文件在不存在的情况下被创建，并且还添加了一些错误检查。

static void appendLineToFile(string filepath, string line) 
{ 
    std::ofstream file; 
    //can't enable exception now because of gcc bug that raises ios_base::failure with useless message 
    //file.exceptions(file.exceptions() | std::ios::failbit); 
    file.open(filepath, std::ios::out | std::ios::app); 
    if (file.fail()) 
     throw std::ios_base::failure(std::strerror(errno)); 

    //make sure write fails with exception if something is wrong 
    file.exceptions(file.exceptions() | std::ios::failbit | std::ifstream::badbit); 

    file << line << std::endl; 
}