[英]How to read from a file using fgets?
我正在嘗試使用fgets讀取“ Danfilez.txt”的內容。 但是,程序完成后會返回一個隨機值,我不確定為什么。 我是編程新手,所以將不勝感激!
int main()
{
FILE* Danfile = fopen ("Danfilez.txt", "w");
char fileinfo [50];// Character arrays for file data //
if (Danfile == NULL)
{
printf ("ERROR\n");
}
else
{
printf("Everything works!\n");
fprintf (Danfile, "Welcome to Dan's file.");
fgets(fileinfo,50,Danfile);
printf("%s\n",fileinfo);
fclose (Danfile); // CLOSES FILE //
}
return 0;
}
由於您正在從文件中讀取和寫入文件,因此您想使用“ w +”打開文件,而不僅僅是“ w”。
但這不能解決問題,因為一旦您寫完該文本,文件中的位置仍然在末尾,因此您還需要重置位置,然后才能使用fseek()
讀取任何內容。
fseek(Danfile,0,SEEK_SET);
使用fopen()時,您將打開選項作為函數的參數傳遞。 這是清單:
"r" - Opens the file for reading. The file must exist.
"w" - Creates an empty file for writing. If a file with the same name already exists,
its content is erased and the file is considered as a new empty file.
"a" - Appends to a file. Writing operations, append data at the end of the
file. The file is created if it does not exist.
"r+" - Opens a file to update both reading and writing. The file must exist.
"w+" - Creates an empty file for both reading and writing.
"a+" - Opens a file for reading and appending.
嘗試使用“ r +”或“ w +” 。 寫入一些文本后,您在文件中的位置將與文本一起向前移動。 使用rewind(FILE * filename)將位置直接移動到文件的開頭。 有關文件處理的更多信息,我建議檢查stdio庫中的內容: https : //www.tutorialspoint.com/c_standard_library/stdio_h.htm
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