C Input/Output (scanf, printf)

🔤 C Input and Output – Using printf() and scanf()

In C programming, printf() is used to display output to the user, while scanf() is used to take input from the user. These functions are part of the standard input/output library (stdio.h).

🔹 printf() – Output Function

The printf() function is used to print text, variables, and formatted data to the screen.

📝 Example: Printing a Message

This simple program displays a greeting message.

#include <stdio.h>

int main() {
    printf("Hello, C Programmer!\n");
    return 0;
}
  

🔹 scanf() – Input Function

The scanf() function is used to get input from the user. It requires the address of the variable using the & operator.

📝 Example: Taking Input from the User

This program asks for your name and age, then prints it back.

#include <stdio.h>

int main() {
    char name[50];
    int age;

    printf("Enter your name: ");
    scanf("%s", name);

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

    printf("Hello %s, you are %d years old.\n", name, age);
    return 0;
}
  

🔸 Format Specifiers

Here are some common format specifiers used in printf() and scanf():

• %d – Integer
• %f – Float
• %c – Character
• %s – String

⚠️ Important Notes

• Always use & before variable names in scanf() except for strings (arrays).
• Use \n inside printf() to print a new line.

🧪 Practice Time

Modify the input program to take your favorite color or your birth year. Experiment with different format specifiers!