Deleting specific line from a text file

Question

I need to delete the last line of a text file. It files user coordinates for each line, but when the user requests a Ctrl + z, I need to delete the last line.

How can I do that?

Answer 1

The usual way to handle C files is to make a new file with what you want from the old one. Then delete the old one (or rename it) and rename the new one to the original one.

Something like

char linha[1000];
FILE *original, *alterado;
original = fopen("original", "r");
alterado = fopen("alterado", "w");
while (fgets(linha, sizeof linha, original)) {
    processalinha(linha);
    fprintf(alterado, "%s", linha);
}
fclose(alterado);
fclose(original);
unlink("original"); // ou rename("original", "original.bak");
rename("alterado", "original");

Of course error validation is missing in the above code!