在这里我们将看到一些在C语言中的基本文件处理操作。以下是这些操作的列表:
- 向文件中写入内容
- 从文件中读取内容
- 在文件中追加内容
向文件中写入内容
请参考以下代码以了解如何向文件中写入内容
示例代码
#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. <p>", filename);
return -1;
} else {
printf("%s: opened in write mode.</p><p>", filename);
}
/* Write content to file */
fprintf(fp, "%s</p><p>", content);
if( !fclose(fp) )
printf("%s: closed successfully.</p><p>", filename);
return 0;
}</p>
输出
sample.txt: opened in write mode.
sample.txt: closed successfully.
2.从文件中读取
查看代码以了解我们如何从文件中读取 创建一个文件(file_read.txt):
您使用C编程语言打开了一个只读模式的文件。
示例代码
#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 <p>", filename);
return;
} else {
printf("%s: opened in read mode.</p><p></p><p>", filename);
}
while ((ch = fgetc(fp) )!= EOF) {
printf ("%c", ch);
}
if (!fclose(fp))
printf("</p><p>%s: closed.</p><p>", filename);
return 0;
}</p>
输出
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.将内容追加到文件中
查看代码以了解如何将行追加到文件中的方法。
创建文件(file_append.txt)
This text was already there in the file.
示例代码
#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("<p>Contents of %s -</p><p></p><p>", filename);
while ((ch = fgetc(fp) )!= EOF) {
printf ("%c", ch);
}
fclose(fp);
fp = fopen(filename, "a");
/* Write content to file */
fprintf(fp, "%s</p><p>", content);
fclose(fp);
fp = fopen(filename, "r");
printf("</p><p>Contents of %s -</p><p>", filename);
while ((ch = fgetc(fp) )!= EOF) {
printf ("%c", ch);
}
fclose(fp);
return 0;
}</p>
输出
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.