File modes in C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to open a file for reading.

C

#include <stdio.h>

int main() {
    FILE *file = fopen("data.txt", "[1]");
    if (file == NULL) {
        perror("Error opening file");
        return 1;
    }
    fclose(file);
    return 0;
}

Drag options to blanks, or click blank then click option'

Aw

Brw

Ca

Dr

Attempts:

3 left

💡 Hint

Common Mistakes

Using "w" which opens the file for writing and truncates it.

Using "a" which opens the file for appending.

The mode "r" opens the file for reading only.

2fill in blank

medium

Complete the code to open a file for writing, creating it if it doesn't exist.

C

#include <stdio.h>

int main() {
    FILE *file = fopen("output.txt", "[1]");
    if (file == NULL) {
        perror("Error opening file");
        return 1;
    }
    fprintf(file, "Hello, World!\n");
    fclose(file);
    return 0;
}

Drag options to blanks, or click blank then click option'

Ar

Bw

Ca

Dr+

Attempts:

3 left

💡 Hint

Common Mistakes

Using "r" which opens the file for reading only.

Using "a" which appends instead of overwriting.

The mode "w" opens the file for writing and creates it if it doesn't exist.

3fill in blank

hard

Fix the error in the code to open a file for appending text.

C

#include <stdio.h>

int main() {
    FILE *file = fopen("log.txt", "[1]");
    if (file == NULL) {
        perror("Error opening file");
        return 1;
    }
    fprintf(file, "New log entry\n");
    fclose(file);
    return 0;
}

Drag options to blanks, or click blank then click option'

Aa

Bw

Cr

Dw+

Attempts:

3 left

💡 Hint

Common Mistakes

Using "w" which overwrites the file.

Using "r" which opens for reading only.

The mode "a" opens the file for appending, writing data at the end.

4fill in blank

hard

Fill both blanks to open a file for reading and writing without truncating it.

C

#include <stdio.h>

int main() {
    FILE *file = fopen("data.txt", "[1][2]");
    if (file == NULL) {
        perror("Error opening file");
        return 1;
    }
    // Read and write operations
    fclose(file);
    return 0;
}

Drag options to blanks, or click blank then click option'

Ar

Bw

C+

Da

Attempts:

3 left

💡 Hint

Common Mistakes

Using "w+" which truncates the file.

Using "a+" which opens for appending.

The mode "r+" opens the file for both reading and writing without truncating it.

5fill in blank

hard

Fill both blanks to open a file for writing and reading, truncating it if it exists.

C

#include <stdio.h>

int main() {
    FILE *file = fopen("report.txt", "[1][2]");
    if (file == NULL) {
        perror("Error opening file");
        return 1;
    }
    // Write and read operations
    fclose(file);
    return 0;
}

Drag options to blanks, or click blank then click option'

Ar

B+

Cw

Da

Attempts:

3 left

💡 Hint

Common Mistakes

Using "r+" which does not truncate the file.

Using "a+" which appends instead of truncating.

The mode "w+" opens the file for both writing (truncating if it exists) and reading.