C language file operation: How to close a file?
Apr 04, 2025 am 11:03 AMC language file operation: How to close a file?
Preface
File operation is a very important topic in the C language. After opening a file, it must be closed to free up system resources and ensure data integrity. This article will guide you on how to close files in C.
grammar
To close a file, use the fclose()
function. The syntax is as follows:
int fclose(FILE *fp);
where fp
is the file pointer to be closed.
Return value
fclose()
function returns 0 to indicate successful closing of the file, otherwise EOF (indicating the end file).
Practical case: read the file and close it
Let's write a C program that reads data from a file and displays it on the screen. The program also demonstrates how to close a file.
#include <stdio.h> int main() { // Declare file pointer FILE *fp; // Open the file fp = fopen("test.txt", "r"); if (fp == NULL) { perror("fopen"); return EXIT_FAILURE; } // Read the character char ch from the file; while ((ch = fgetc(fp)) != EOF) { printf("%c", ch); } // Close the file if (fclose(fp) == EOF) { perror("fclose"); return EXIT_FAILURE; } return 0; }
Run the program
Compile and run the program. It will read the characters from a file named test.txt
and print them to the screen. After closing the file, the system resources will be released.
The above is the detailed content of C language file operation: How to close a file?. For more information, please follow other related articles on the PHP Chinese website!

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