Reading Input from the User in C programming

Reading Input from the User in C

In C programming, reading input from the user is typically done using the scanf function. This function allows you to capture user input from the standard input (usually the keyboard) and store it in variables for further processing.

Using the scanf Function

The scanf function reads formatted input from the standard input. Its syntax is as follows:

scanf("format_string", &variable1, &variable2, ...);

Explanation:

• "format_string": A format string that specifies the type of data expected. For example, %d for integers, %f for floats, and %s for strings.
• &variable: The address of the variable where the input value will be stored. The ampersand (&) is used to pass the address of the variable to scanf.

Example

Example: Reading an Integer and a Float from the User

#include <stdio.h>

int main() {
    int age;
    float height;

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

    printf("Enter your height (in meters): ");
    scanf("%f", &height);

    // Output the values
    printf("Your age is %d years.\\n", age);
    printf("Your height is %.2f meters.\\n", height);

    return 0;
}

In this example:

• scanf("%d", &age); reads an integer from the user and stores it in the variable age.
• scanf("%f", &height); reads a floating-point number from the user and stores it in the variable height.
• The printf function then displays the entered values.

Additional Notes

scanf is a powerful function, but it is important to handle potential errors and edge cases:

• Ensure the format string matches the type of data you expect to read.
• Be aware of buffer overflows when reading strings. For safer string input, consider using fgets.

Note:
Always validate user input to ensure it meets expected formats and values. This can prevent unexpected behavior or errors in your program.