User Input/Output in C

We have already learned how the printf() function is used to output values in C. Another method, which goes by the name, scanf(), is used to get user input.

The scanf() function takes two arguments:

• the format specifier of the variable (as shown in the example below)
• the reference operator (&myNum), which stores the memory address of the variable. This is where the input data goes to.

Syntax:

        scanf("format specifier", &variable_name);
    

& specifies the address of the variable.

One such example demonstrates how a program takes input from the user.

        
#include <stdio.h>

int main() {
    int marks;
    char name[30];
    printf("Enter student's name: ");
    scanf("%s", name);
    printf("Enter marks in Maths: ");
    scanf("%d", &marks);

    printf("Hello %s! You have scored %d in Maths!", name, marks);
    return 0;
}
        
    

Input:

        
Enter student's name: Rohan
Enter marks in Maths: 98
        
    

Output:

        
Hello Rohan! You have scored 98 in Maths!
        
    

You must note that we didn’t have to specify the reference operator (&) in cases of strings if we have specified the size of the strings already. This is an exception.