# Reading Input from the Terminal

Reading input from the terminal allows your C programs to interact with users and receive data during runtime. In this section, we'll explore the standard input functions, particularly `scanf()`, which is commonly used for reading input in C.

## The `scanf()` Function

The `scanf()` function is part of the standard input/output library in C and is used for reading formatted input. It allows you to receive user input and store it in variables. Here's a basic example:

```c
#include <stdio.h>

int main() {
    int age;

    // Prompt user for input
    printf("Enter your age: ");
    
    // Read integer input from the user
    scanf("%d", &age);

    // Display the entered age
    printf("You entered: %d\n", age);

    return 0;
}
```

In this example, `%d` is the format specifier for an integer, and `&age` represents the memory address of the `age` variable.

## Format Specifiers for `scanf()`

`scanf()` supports various format specifiers for different types of input:

* `%d`: Integer
* `%f`: Float
* `%lf`: Double
* `%c`: Character
* `%s`: String

```c
#include <stdio.h>

int main() {
    int num;
    float salary;
    char grade;
    char name[50];

    // Reading different types of input
    scanf("%d", &num);
    scanf("%f", &salary);
    // Note the space before %c to consume the newline character
    scanf(" %c", &grade);  
    scanf("%s", name);

    // Displaying the entered values
    printf("Number: %d\n", num);
    printf("Salary: %.2f\n", salary);
    printf("Grade: %c\n", grade);
    printf("Name: %s\n", name);

    return 0;
}
```

## Reading Strings with Spaces

Reading strings with spaces using `scanf()` requires a different approach. The `%s` specifier stops reading at the first whitespace. Instead, you can use the `%[^\n]` specifier to read a whole line:

```c
#include <stdio.h>

int main() {
    char sentence[100];

    // Reading a whole line
    printf("Enter a sentence: ");
    scanf(" %[^\n]", sentence);

    // Displaying the entered sentence
    printf("You entered: %s\n", sentence);

    return 0;
}
```

## Handling Multiple Inputs

To read multiple inputs in a single `scanf()` call, you can use multiple format specifiers separated by spaces:

```c
#include <stdio.h>

int main() {
    int num1, num2;

    // Reading two integers
    printf("Enter two numbers separated by a space: ");
    scanf("%d %d", &num1, &num2);

    // Displaying the entered numbers
    printf("Numbers entered: %d and %d\n", num1, num2);

    return 0;
}
```

## Conclusion

Reading input from the terminal is a crucial aspect of interactive C programming. The `scanf()` function provides a flexible way to receive user input in various formats. Understanding the appropriate format specifiers and handling input effectively enhances the usability of your C programs.

In the upcoming sections, we'll explore more advanced concepts in C programming. If you have specific questions or areas you'd like to delve into further, feel free to ask. Happy coding!