#include <stdio.h>
int main() {
    int num;
    
    printf("Enter a number: ");
    scanf("%d", &num);
    
    printf("You entered: %d\n", num);
    
    char ch;

    printf("Press a key: ");
    ch = getch();

    printf("You pressed: %c\n", ch);
    
    char chr;

    printf("Enter a character: ");
    chr = getchar();

    printf("You entered: %c\n", chr);
    
    return 0;
}

#include <stdio.h>

int main() {
    int num = 42;
    printf("The number is: %d\n", num);
    
    char str[] = "Hello, C!";
    puts(str);
    
    char ch = 'A';
    putchar(ch);
    
    return 0;
}

#include <stdio.h>

int main() {
    FILE *file = fopen("example.txt", "r");
    if (file != NULL) {
        char buffer[100];
        fscanf(file, "%s", buffer);
        printf("Read from file: %s\n", buffer);
        fclose(file);
    }
    return 0;
}

#include <stdio.h>

int main() {
    FILE *file = fopen("example.txt", "r");
    if (file == NULL) {
        perror("Error opening file");
        return 1; // Exit with an error code
    }

    // Continue with file operations

    fclose(file);
    return 0;
}

Input and output operations in c are crucial for interacting with the user and the external environment. Here are the Functions

1. Input Functions - scanf, getchar, getch
2. Output Function - printf, pus , putchar
3. File I/O - fopen, fclose, fread, fwrite, fprintf, and fscanf

The functions which takes input from the user are called Input Functions.
Here are some of the functions

scanf - Read input from standard input with format specifiers
Example: scanf("%d", &num);

getchar - Read a single character from standard input
Example: char ch = getchar();

getch - Read a single character without waiting for Enter
Example: char ch = getch();

The Functions which shows any text to the user are called output functions.
Here are the Output functions used

printf - Formatted output to the standard output (console)
Example: printf("Hello World!");

puts - Outputs a string to the standard output
Example: puts("This is a string.");

putchar - Outputs a character to the standard output
Example: putchar('A');

File I/O Functions used to upload, access and modify the files.
Here are the File I/O Functions

fopen - Opens a file and returns a file pointer
Example: FILE *file = fopen("example.txt", "w");

fclose - Closes a file
Example: fclose(file);

fread - Reads a block of data from a
Example: file fread(buffer, sizeof(char), 100, file);

fwrite - Writes a block of data to a
Example: file fwrite(data, sizeof(int), 10, file);

fprintf - Formatted output to a file
Example: fprintf(file, "Data: %d\n", data);

fscanf - Reads formatted data from a file
Example: fscanf(file, "%s", str);