C 파일 처리 기본 사항

#include  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; }

sample.txt: opened in write mode. sample.txt: closed successfully.

#include  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; }

file_read.txt: opened in read mode. You have opened a file using C programming language, in read-only mode. file_read.txt: closed.

This text was already there in the file.

#include  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; }

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.