File Handling – Let us C

Binary File Write and Read

Pravesh Agrawal — Sat, 02 Dec 2023 11:08:34 +0000

#include 

struct Student {
    char name[50];
    int age;
    float gpa;
};

int main() {
    // Binary file write and read
    FILE *binaryFile;
    struct Student student;

    // Writing to a binary file
    binaryFile = fopen("students.dat", "wb");
    if (binaryFile != NULL) {
        strcpy(student.name, "John Doe");
        student.age = 20;
        student.gpa = 3.75;

        fwrite(&student, sizeof(struct Student), 1, binaryFile);

        fclose(binaryFile);
        printf("Student data written to the binary file.\n");
    } else {
        printf("Unable to open the binary file.\n");
    }

    // Reading from a binary file
    binaryFile = fopen("students.dat", "rb");
    if (binaryFile != NULL) {
        fread(&student, sizeof(struct Student), 1, binaryFile);

        fclose(binaryFile);
        printf("Student Data:\nName: %s\nAge: %d\nGPA: %.2f\n", student.name, student.age, student.gpa);
    } else {
        printf("Unable to open the binary file.\n");
    }

    return 0;
}

File Read and Display

Pravesh Agrawal — Sat, 02 Dec 2023 11:08:11 +0000

#include 

int main() {
    // File read and display
    FILE *file;
    char buffer[100];

    file = fopen("display.txt", "r");
    if (file != NULL) {
        while (fgets(buffer, sizeof(buffer), file) != NULL) {
            printf("%s", buffer);
        }
        fclose(file);
    } else {
        printf("Unable to open the file.\n");
    }

    return 0;
}

File Append

Pravesh Agrawal — Sat, 02 Dec 2023 11:07:48 +0000

#include 

int main() {
    // File append
    FILE *file;
    char data[] = "This text will be appended.\n";

    file = fopen("append.txt", "a");
    if (file != NULL) {
        fprintf(file, "%s", data);
        fclose(file);
        printf("Data appended to the file.\n");
    } else {
        printf("Unable to open the file.\n");
    }

    return 0;
}

File Copy

Pravesh Agrawal — Sat, 02 Dec 2023 11:07:25 +0000

#include 

int main() {
    // File copy
    FILE *sourceFile, *destinationFile;
    char buffer[100];

    sourceFile = fopen("source.txt", "r");
    destinationFile = fopen("destination.txt", "w");

    if (sourceFile != NULL && destinationFile != NULL) {
        while (fgets(buffer, sizeof(buffer), sourceFile) != NULL) {
            fputs(buffer, destinationFile);
        }
        fclose(sourceFile);
        fclose(destinationFile);
        printf("File copied successfully.\n");
    } else {
        printf("Unable to open files.\n");
    }

    return 0;
}

File Input and Output

Pravesh Agrawal — Sat, 02 Dec 2023 11:07:05 +0000

#include 

int main() {
    // File input and output
    FILE *file;
    char data[] = "Hello, File Handling!\n";

    // Writing to a file
    file = fopen("output.txt", "w");
    if (file != NULL) {
        fprintf(file, "%s", data);
        fclose(file);
        printf("Data written to the file.\n");
    } else {
        printf("Unable to open the file.\n");
    }

    // Reading from a file
    file = fopen("output.txt", "r");
    if (file != NULL) {
        char buffer[100];
        fgets(buffer, sizeof(buffer), file);
        fclose(file);
        printf("Data read from the file: %s", buffer);
    } else {
        printf("Unable to open the file.\n");
    }

    return 0;
}