Correct Answer: 0
Explanation: `feof()` in C returns 0 if the end-of-file (EOF) indicator is not set on the file stream. This indicates that there is more data available to be read from the file.
Correct Answer: exit()
Explanation: The `exit()` function in C is used to terminate the program immediately and return control to the operating system. It is often used in conjunction with `fprintf()` or `printf()` to print a custom error message before exiting.
Correct Answer: Before reading from a file
Explanation: In C, `feof()` is typically used before reading from a file to check if the end-of-file (EOF) indicator is set. This helps to determine if all data has been read from the file before attempting to read more data.
Correct Answer: Checks for file errors
Explanation: The `ferror()` function in C checks for file errors by examining the error indicator associated with a file stream. It returns a non-zero value if an error occurred on the file stream.
Correct Answer: Clears the error and end-of-file indicators
Explanation: The `clearerr()` function in C clears the error and end-of-file indicators for a given file stream (`FILE *`). It resets both indicators so that subsequent operations on the file stream can be performed without the influence of previous error conditions.
Correct Answer: strerror()
Explanation: The `strerror()` function in C can be used to retrieve a string describing the last error encountered during a file operation. It takes an error code as input and returns a pointer to a string containing the error message.
Correct Answer: Prints the last encountered error message
Explanation: `perror()` in C prints the last encountered error message corresponding to a file operation that encountered an error. If called without a preceding error condition, it typically prints a generic error message indicating no specific file error.
Correct Answer: When encountering an error during a file operation
Explanation: `ferror()` in C returns a non-zero value when encountering an error during a file operation. It checks the error indicator associated with a file stream and returns a non-zero value if an error occurred.
Correct Answer: 1
Explanation: `feof()` in C returns a non-zero value (typically 1) if the end-of-file (EOF) indicator is set on the file stream. This indicates that all data has been read from the file and further read operations will return EOF.
Correct Answer: EOF
Explanation: The `EOF` macro in C is used to indicate the end-of-file (EOF) condition when reading from a file stream. It is returned by functions like `getc()` and `fgetc()` when the end of the file is reached.
Correct Answer: Moves the file pointer to a specified position
Explanation: The `fseek()` function in C is used to move the file pointer associated with a file stream to a specified position. It allows random access within a file by specifying a new position relative to a reference point.
Correct Answer: ftell()
Explanation: The `ftell()` function in C is used to return the current position of the file pointer within a file stream. It returns a `long int` value representing the current offset from the beginning of the file.
Correct Answer: Bytes
Explanation: `ftell()` in C returns the current position of the file pointer in bytes from the beginning of the file. It provides a numeric value indicating the offset within the file stream.
Correct Answer: Moves the file pointer to the beginning of the file
Explanation: The `rewind()` function in C moves the file pointer associated with a file stream to the beginning of the file. It resets the file pointer to the start, allowing subsequent operations to begin reading or writing from the beginning.
Correct Answer: fseek()
Explanation: The `fseek()` function in C is used to set the file position indicator for a file stream to a specified position. It allows you to move the file pointer relative to a reference point within the file.
Correct Answer: 0
Explanation: `fseek()` in C returns 0 on success, indicating that the file position indicator was successfully set to the specified position. If an error occurs, it returns a non-zero value or `EOF`.
Correct Answer: It resets both the error and end-of-file indicators
Explanation: The `rewind()` function in C moves the file pointer to the beginning of the file and resets both the error and end-of-file indicators associated with the file stream.
Correct Answer: fsetpos()
Explanation: The `fsetpos()` function in C is used to set the file position indicator for a file stream using an absolute position specified by a `fpos_t` object. It allows random access to a specific position within a file.
Correct Answer: -1
Explanation: `ftell()` in C returns -1 on error, indicating that an error occurred while attempting to determine the current position of the file pointer within the file stream.
Correct Answer: long int
Explanation: The `ftell()` function in C returns a `long int` value representing the current position of the file pointer within the file stream. This allows for large file offsets to be handled properly.
Correct Answer: Moves the file pointer to the beginning of the file
Explanation: When you use `rewind()` immediately after opening a file in “r” mode using `fopen()` in C, it moves the file pointer to the beginning of the file. This prepares the file stream for subsequent read operations from the start of the file.
Correct Answer: None of the above
Explanation: There is no standard C function to move the file pointer directly to the end of the file. However, you can achieve this by using `fseek()` with a seek offset of 0 from the end (`SEEK_END`).
Correct Answer: void
Explanation: The `rewind()` function in C does not return a value (`void`). It moves the file pointer associated with a file stream to the beginning of the file and resets both the error and end-of-file indicators.
Correct Answer: fseek()
Explanation: The `fseek()` function in C is used to move the file pointer to a specified byte offset from the beginning of the file. It allows random access within a file by setting the file position indicator to a specific position.
Correct Answer: <stdio.h>
Explanation: The `fseek()`, `ftell()`, and `rewind()` functions are declared in the `<stdio.h>` header file in C. This header file provides declarations for standard input and output operations, including file handling functions.
Correct Answer: Moves the file pointer to the end of the file
Explanation: Using `fseek()` with `SEEK_END` in C moves the file pointer to the end of the file. This allows you to perform operations at the end of the file, such as appending data or reading data from the end.
Correct Answer: SEEK_SET
Explanation: The `SEEK_SET` macro in C is used as a seek mode in `fseek()` to specify the position relative to the beginning of the file. It allows you to set the file position indicator to an absolute position within the file.
Correct Answer: -1
Explanation: `ftell()` in C returns -1 if it encounters an error while attempting to determine the current position of the file pointer within the file stream. This indicates that an error occurred during the operation.
Correct Answer: fsetpos()
Explanation: The `fsetpos()` function in C is used to set the file position indicator for a file stream using a position object (`fpos_t`). It allows you to set the file pointer to a specific position within the file for random access.
Correct Answer: long int
Explanation: The `ftell()` function in C returns a `long int` value representing the current position of the file pointer within the file stream. This data type allows for large file offsets to be handled properly.
#include <stdio.h>
int main() {
FILE *fp;
char ch;
fp = fopen("file.txt", "r");
if (fp == NULL) {
printf("File cannot be opened.\n");
} else {
while ((ch = fgetc(fp)) != EOF) {
putchar(ch);
}
fclose(fp);
}
return 0;
}
Correct Answer: Opens and reads the contents of “file.txt” character by character
Explanation: This code snippet opens “file.txt” in read mode (`”r”`), reads and outputs each character until EOF, and then closes the file.
#include <stdio.h>
int main() {
FILE *fp;
char str[50];
fp = fopen("file.txt", "w");
fprintf(fp, "Hello, World!");
fclose(fp);
fp = fopen("file.txt", "r");
fscanf(fp, "%s", str);
printf("%s\n", str);
fclose(fp);
return 0;
}
Correct Answer: Hello, World!
Explanation: This code snippet first writes “Hello, World!” to “file.txt”, then reads and prints the content of “file.txt” using `fscanf()`.
#include <stdio.h>
int main() {
FILE *fp;
char str[] = "This is a test.";
fp = fopen("file.txt", "w");
fputs(str, fp);
fclose(fp);
return 0;
}
Correct Answer: Writes “This is a test.” to “file.txt”
Explanation: This code snippet opens “file.txt” in write mode (`”w”`), writes the string “This is a test.” to the file using `fputs()`, and then closes the file.
#include <stdio.h>
int main() {
FILE *fp;
char str[50];
fp = fopen("file.txt", "r");
if (fp == NULL) {
printf("File cannot be opened.\n");
} else {
// Missing code to read from file
printf("Content: %s\n", str);
fclose(fp);
}
return 0;
}
Correct Answer: `fgets(str, sizeof(str), fp);`
Explanation: To read from “file.txt” using `fgets()`, the correct code should be `fgets(str, sizeof(str), fp);`.
#include <stdio.h>
int main() {
FILE *fp;
fp = fopen("file.txt", "a");
fprintf(fp, "Appending new line.\n");
fclose(fp);
return 0;
}
Correct Answer: Opens “file.txt” and appends “Appending new line.” to it
Explanation: This code snippet opens “file.txt” in append mode (`”a”`), appends the string “Appending new line.\n” to the end of the file using `fprintf()`, and then closes the file.
#include <stdio.h>
int main() {
FILE *fp;
char str[] = "This is a test.";
fp = fopen("file.txt", "w+");
fputs(str, fp);
return 0;
}
Correct Answer: Writes “This is a test.” to “file.txt” and opens it for reading and writing
Explanation: This code snippet opens “file.txt” in write mode (`”w+”`), writes the string “This is a test.” to the file using `fputs()`, and prepares the file for both reading and writing.
#include <stdio.h>
int main() {
FILE *fp;
fp = fopen("file.txt", "r");
fseek(fp, 0, SEEK_END);
printf("Size of file.txt: %ld bytes\n", ftell(fp));
fclose(fp);
return 0;
}
Correct Answer: Prints the size of “file.txt” in bytes
Explanation: This code snippet opens “file.txt” in read mode (`”r”`), uses `fseek()` with `SEEK_END` to move the file pointer to the end of the file, uses `ftell()` to get the current position (which represents the file size), and then prints the size in bytes.
#include <stdio.h>
int main() {
FILE *fp;
fp = fopen("file.txt", "w");
fprintf(fp, "Hello, World!");
fseek(fp, 0, SEEK_SET);
fputs("Goodbye, World!", fp);
fclose(fp);
return 0;
}
Correct Answer: Overwrites “Hello, World!” with “Goodbye, World!” in “file.txt”
Explanation: This code snippet opens “file.txt” in write mode (`”w”`), writes “Hello, World!” using `fprintf()`, moves the file pointer to the beginning using `fseek()` with `SEEK_SET`, and then overwrites “Hello, World!” with “Goodbye, World!” using `fputs()`.
#include <stdio.h>
int main() {
FILE *fp;
char str[] = "Hello, World!";
fp = fopen("file.txt", "w+");
fprintf(fp, "%s", str);
rewind(fp);
fscanf(fp, "%s", str);
printf("%s\n", str);
fclose(fp);
return 0;
}
Correct Answer: Writes “Hello, World!” to “file.txt” and reads and prints it
Explanation: This code snippet opens “file.txt” in read-write mode (`”w+”`), writes “Hello, World!” using `fprintf()`, uses `rewind()` to move the file pointer to the beginning, reads “Hello, World!” using `fscanf()`, and prints it using `printf()`.
#include <stdio.h>
int main() {
FILE *fp;
char str[50];
fp = fopen("file.txt", "r");
if (fp == NULL) {
printf("File cannot be opened.\n");
} else {
fgets(str, sizeof(str), fp);
printf("%s", str);
fclose(fp);
}
return 0;
}
Correct Answer: Reads and prints the contents of “file.txt” line by line
Explanation: This code snippet opens “file.txt” in read mode (`”r”`), reads each line using `fgets()` until EOF or when `sizeof(str)` characters have been read, and prints each line using `printf()`.
#include <stdio.h>
int main() {
FILE *fp;
char ch;
fp = fopen("file.txt", "r");
if (fp == NULL) {
printf("File cannot be opened.\n");
} else {
while ((ch = fgetc(fp)) != EOF) {
putchar(ch);
}
fclose(fp);
}
return 0;
}
Correct Answer: Opens and reads the contents of “file.txt” character by character
Explanation: This code snippet opens “file.txt” in read mode (`”r”`), reads each character from the file using `fgetc()` until EOF, and prints each character to the standard output using `putchar()`.
#include <stdio.h>
int main() {
FILE *fp;
char str[50];
fp = fopen("file.txt", "w");
fprintf(fp, "Hello, World!");
fclose(fp);
fp = fopen("file.txt", "r");
fscanf(fp, "%s", str);
printf("%s\n", str);
fclose(fp);
return 0;
}
Correct Answer: Hello, World!
Explanation: This code snippet first writes “Hello, World!” to “file.txt” using `fprintf()`, then reads the content of “file.txt” using `fscanf()` and prints it using `printf()`.
#include <stdio.h>
int main() {
FILE *fp;
char str[] = "This is a test.";
fp = fopen("file.txt", "w");
fputs(str, fp);
fclose(fp);
return 0;
}
Correct Answer: Writes “This is a test.” to “file.txt”
Explanation: This code snippet opens “file.txt” in write mode (`”w”`), writes the string “This is a test.” to the file using `fputs()`, and then closes the file.
#include <stdio.h>
int main() {
FILE *fp;
char str[50];
fp = fopen("file.txt", "r");
if (fp == NULL) {
printf("File cannot be opened.\n");
} else {
// Missing code to read from file
printf("Content: %s\n", str);
fclose(fp);
}
return 0;
}
Correct Answer: `fgets(str, sizeof(str), fp);`
Explanation: To read from “file.txt” using `fgets()`, the correct code should be `fgets(str, sizeof(str), fp);`.
#include <stdio.h>
int main() {
FILE *fp;
fp = fopen("file.txt", "a");
fprintf(fp, "Appending new line.\n");
fclose(fp);
return 0;
}
Correct Answer: Opens “file.txt” and appends “Appending new line.” to it
Explanation: This code snippet opens “file.txt” in append mode (`”a”`), appends the string “Appending new line.\n” to the end of the file using `fprintf()`, and then closes the file.
#include <stdio.h>
int main() {
FILE *fp;
char str[] = "This is a test.";
fp = fopen("file.txt", "w+");
fputs(str, fp);
return 0;
}
Correct Answer: Writes “This is a test.” to “file.txt” and opens it for reading and writing
Explanation: This code snippet opens “file.txt” in write mode (`”w+”`), writes the string “This is a test.” to the file using `fputs()`, and prepares the file for both reading and writing.
#include <stdio.h>
int main() {
FILE *fp;
fp = fopen("file.txt", "r");
fseek(fp, 0, SEEK_END);
printf("Size of file.txt: %ld bytes\n", ftell(fp));
fclose(fp);
return 0;
}
Correct Answer: Prints the size of “file.txt” in bytes
Explanation: This code snippet opens “file.txt” in read mode (`”r”`), uses `fseek()` with `SEEK_END` to move the file pointer to the end of the file, uses `ftell()` to get the current position (which represents the file size), and then prints the size in bytes.
#include <stdio.h>
int main() {
FILE *fp;
fp = fopen("file.txt", "w");
fprintf(fp, "Hello, World!");
fseek(fp, 0, SEEK_SET);
fputs("Goodbye, World!", fp);
fclose(fp);
return 0;
}
Correct Answer: Overwrites “Hello, World!” with “Goodbye, World!” in “file.txt”
Explanation: This code snippet opens “file.txt” in write mode (`”w”`), writes “Hello, World!” using `fprintf()`, moves the file pointer to the beginning using `fseek()` with `SEEK_SET`, and then overwrites “Hello, World!” with “Goodbye, World!” using `fputs()`.
#include <stdio.h>
int main() {
FILE *fp;
char str[50];
fp = fopen("file.txt", "r");
if (fp == NULL) {
printf("File cannot be opened.\n");
} else {
fgets(str, sizeof(str), fp);
printf("%s", str);
fclose(fp);
}
return 0;
}
Correct Answer: Reads and prints the contents of “file.txt” line by line
Explanation: This code snippet opens “file.txt” in read mode (`”r”`), reads each line using `fgets()` until EOF or when `sizeof(str)` characters have been read, and prints each line using `printf()`.
#include <stdio.h>
int main() {
FILE *fp;
char str[50];
fp = fopen("file.txt", "a");
fprintf(fp, "Appending new line.\n");
fclose(fp);
return 0;
}
Correct Answer: Opens “file.txt” and appends “Appending new line.” to it
Explanation: This code snippet opens “file.txt” in append mode (`”a”`), appends the string “Appending new line.\n” to the end of the file using `fprintf()`, and then closes the file.