001
02.10.2002, 12:24 Uhr
void*
Generic Pointer
(Operator)
|
Hallo!
Hier auch mal ein Beitrag von mir  ...
Ist nicht schön, aber "straightforward" und simpel.
| C++: |
#include <cstdio>
#include <string>
// ...
// Description: This function deletes a line out of a file.
// Parameters: name of the file out of which a line shall be deleted,
// number of line to be deleted (count starts at 0)
// Return value: number of characters that were deleted (including '\n'), -1
// file could not be opened for reading, -2 error reading file, -3 error opening
// file for writing, -4 error writing file, 0 line number 'line' does not exist
int delline(const char* name, size_t line)
{
// read the whole file and write it into buffer
std::FILE *input=std::fopen(name, "r");
if(!input)
return(-1);
std::string buffer;
int c;
while(EOF!=(c=fgetc(input)))
{
buffer+=static_cast<char>(c);
}
if(!feof(input)) // Builder doesn't want eof() in std?!
{
(void)std::fclose(input);
return(-2);
}
if(EOF==std::fclose(input))
return(-2);
// search the start of the line that has to be deleted
unsigned int currentLine=0;
std::string::size_type currentPosition=0, oldPosition=0;
while(currentLine<line)
{
currentPosition=buffer.find_first_of('\n', oldPosition);
if(std::string::npos==currentPosition)
return(0);
oldPosition=++currentPosition;
if(buffer.length()<=oldPosition)
return(0);
++currentLine;
}
// find the end of the current line
std::string::size_type endPosition=buffer.find_first_of('\n', currentPosition);
// determine number of chars to be deleted...and get rid of them
int numberOfCharsDeleted= std::string::npos==endPosition ? buffer.length()-currentPosition : endPosition-currentPosition+1;
buffer.erase(currentPosition, numberOfCharsDeleted);
// write the modified buffer
std::FILE *output=std::fopen(name, "w");
if(!output)
return(-3);
if(0>fprintf(output, "%s", buffer.c_str()))
{
(void)std::fclose(output);
return(-4);
}
if(EOF==std::fclose(output))
{
return(-4);
}
return(numberOfCharsDeleted);
}
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MfG
void*
--
Gruß
void* |
