Read a line from text file and delete it

c, file, winapi, windows

Solution

here's an example:

char* inFileName = "test.txt";
char* outFileName = "tmp.txt";
FILE* inFile = fopen(inFileName, "r");
FILE* outFile = fopen(outFileName, "w+");
char line [1024]; // maybe you have to user better value here
int lineCount = 0;

if( inFile == NULL )
{
    printf("Open Error");
}

while( fgets(line, sizeof(line), inFile) != NULL )
{
    if( ( lineCount % 2 ) != 0 )
    {
        fprintf(outFile, "%s", line);
    }

    lineCount++;
}


fclose(inFile);
fclose(outFile);

// possible you have to remove old file here before
if( !rename(inFileName, outFileName) )
{
    printf("Rename Error");
}

Problem

I want to read a text file line by line, perform some checks, and if the line is not required, delete it. I have done the code for reading line, but I don't know how to delete that line if it is not required by me. Please help me find the simplest method for deleting the line. Here is my code snippet what I tried: ``` char ip[32]; int port; DWORD dwWritten; FILE *fpOriginal, *fpOutput; HANDLE hFile,tempFile; hFile=CreateFile("Hell.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0); tempFile=CreateFile("temp.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0); WriteFile(hFile,"10.0.1.25 524192\r\n\r\n10.0.1.25 524193\r\n\r\n",strlen("10.0.1.25 524192\r\n\r\n10.0.1.25 524193\r\n\r\n"),&dwWritten,0); fpOriginal = fopen("Hell.txt", "r+"); fpOutput = fopen("temp.txt", "w+"); while (fscanf(fpOriginal, " %s %d", ip, &port) > 0) { printf("\nLine1:"); printf("ip: %s, port: %d", ip, port); char portbuff[32], space[]=" "; sprintf(portbuff, "%i",port); strcat(ip," "); strcat(ip,portbuff); if(port == 524192) printf("\n Delete this Line now"); else WriteFile(tempFile,ip,strlen(ip),&dwWritten,0); } fclose(fpOriginal); fclose(fpOutput); CloseHandle(hFile); CloseHandle(tempFile); remove("Hell.txt"); if(!(rename("temp.txt","Bye.txt"))) { printf("\ncould not rename\n"); } else printf("\nRename Done\n"); //remove ("Hell.txt"); ```

Original source