Input and Output Functions

Formatted I/O: printf() and scanf()

These functions use Format Specifiers to tell the computer what kind of data is being moved.

• printf(): Sends data to the screen.

#include <stdio.h>

int main() {
    int age;
    float weight;
    char grade;

    printf("Enter your grade (A/B/C): ");
    scanf(" %c", &grade); // Note the space before %c to skip any leftover newline characters

    printf("Enter your age: ");
    scanf("%d", &age);

    printf("Enter your weight: ");
    scanf("%f", &weight);

    printf("\n--- Summary ---\n");
    printf("Grade: %c | Age: %d | Weight: %.1f kg\n", grade, age, weight);

    return 0;
}

Expected Output:

Enter your grade (A/B/C): A
Enter your age: 25
Enter your weight: 70.5

--- Summary ---
Grade: A | Age: 25 | Weight: 70.5 kg

3. Character & String I/O

Sometimes you don't need formatted data—just raw characters or lines of text.

• getchar() / putchar(): For a single character.

#include <stdio.h>

int main() {
    char ch;

    printf("Type a character: ");
    ch = getchar(); // Read one char
    
    printf("You typed: ");
    putchar(ch);    // Print one char
    printf("\n");

    return 0;
}

Expected Output:

Type a character: Z
You typed: Z

Specifier

DataType

%dInteger

%fFloat

%lfDouble

%cCharacter

%sString (Array of characters).