// C program to implement
// the above approach
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// Driver code
int main()
{
FILE* ptr;
char ch;
// Opening file in reading mode
ptr = fopen("test.txt", "r");
if (NULL == ptr) {
printf("file can't be opened
");
}
printf("content of this file are
");
// Printing what is written in file
// character by character using loop.
do {
ch = fgetc(ptr);
printf("%c", ch);
// Checking if character is not EOF.
// If it is EOF stop eading.
} while (ch != EOF);
// Closing the file
fclose(ptr);
return 0;
}
FILE *in_file = fopen("name_of_file", "r"); // read only
FILE *out_file = fopen("name_of_file", "w"); // write only
// test for files not existing.
if (in_file == NULL || out_file == NULL)
{
printf("Error! Could not open file
");
exit(-1); // must include stdlib.h
}
// write to file vs write to screen
fprintf(file, "this is a test %d
", integer); // write to file
fprintf(stdout, "this is a test %d
", integer); // write to screen
printf( "this is a test %d
", integer); // write to screen
// read from file/keyboard. remember the ampersands!
fscanf(file, "%d %d", &int_var_1, &int_var_2);
fscanf(stdin, "%d %d", &int_var_1, &int_var_2);
scanf( "%d %d", &int_var_1, &int_var_2);