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法學研究C 中檔案處理基礎
這裡我們將看到 C 中一些基本檔案處理操作。操作如下所示。
- 寫入檔案
- 從檔案讀取
- 在檔案中追加
寫入檔案
檢視程式碼以瞭解如何寫入檔案
示例程式碼
#include <stdio.h>
int main() {
FILE *fp;
char *filename = "sample.txt";
char *content = "Hey there! You've successfully created a file with content in c programming language.";
/* open for writing */
fp = fopen(filename, "w");
if( fp == NULL ) {
printf("%s: failed to open.
", filename);
return -1;
} else {
printf("%s: opened in write mode.
", filename);
}
/* Write content to file */
fprintf(fp, "%s
", content);
if( !fclose(fp) )
printf("%s: closed successfully.
", filename);
return 0;
}輸出
sample.txt: opened in write mode. sample.txt: closed successfully.
2.從檔案中讀取
檢視程式碼以瞭解如何從檔案中讀取（建立一個檔案 (file_read.txt)）
您使用 C 程式語言以只讀模式打開了一個檔案。
示例程式碼
#include <stdio.h>
int main() {
FILE *fp;
char *filename = "file_read.txt";
char ch;
/* open for writing */
fp = fopen(filename, "r");
if (fp == NULL) {
printf("%s does not exists
", filename);
return;
} else {
printf("%s: opened in read mode.
", filename);
}
while ((ch = fgetc(fp) )!= EOF) {
printf ("%c", ch);
}
if (!fclose(fp))
printf("
%s: closed.
", filename);
return 0;
}輸出
file_read.txt: opened in read mode. You have opened a file using C programming language, in read-only mode. file_read.txt: closed.
3. 在檔案中追加
檢視程式碼以瞭解如何將行追加到檔案中。
建立一個檔案 (file_append.txt)
This text was already there in the file.
示例程式碼
#include <stdio.h>
int main() {
FILE *fp;
char ch;
char *filename = "file_append.txt";
char *content = "This text is appeneded later to the file, using C programming.";
/* open for writing */
fp = fopen(filename, "r");
printf("
Contents of %s -
", filename);
while ((ch = fgetc(fp) )!= EOF) {
printf ("%c", ch);
}
fclose(fp);
fp = fopen(filename, "a");
/* Write content to file */
fprintf(fp, "%s
", content);
fclose(fp);
fp = fopen(filename, "r");
printf("
Contents of %s -
", filename);
while ((ch = fgetc(fp) )!= EOF) {
printf ("%c", ch);
}
fclose(fp);
return 0;
}輸出
Contents of file_append.txt - This text was already there in the file. Appending content to file_append.txt... Content of file_append.txt after 'append' operation is - This text was already there in the file. This text is appeneded later to the file, using C programming.
更新於： 2020 年 11 月 18 日
1 千次 + 檢視
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