Is this a correct usage of struct? - c

Question

#include <stdio.h>
int main()
{
struct database
{
char name[10];
int number;
int roll;
};
struct database s1,s2;
printf("enter name, number , roll: ");
scanf("%c%d%d",&s1.name,&s1.number,&s1.roll);
scanf("%c%d%d",&s2.name,&s2.number,&s2.roll);
printf("Entered value is :");
printf("%c%d%d",s1.name,s1.number,s1.roll);
printf("%c%d%d",s2.name,s2.number,s2.roll);
}
I've been trying to get output but I don't know if this correct Or should I access them individually? Help would be very much appreciated! thanks :)

Answer 1

If you need the specific struct only within the function body, then your declaration will suffice. But, note that if you want a struct to be used throughout the program, then it needs to be defined like this:
struct database {
...
};
int main(void) {
struct database s1, s2;
...
}
Also, you're trying to accept a single char value:
scanf("%c%d%d", &name, ...);
// --^^--
Here, you are expected to get a char from the user:
scanf("%9s%d%d", name, ...);
Note: The %9s is specifically given to prevent input buffer overflow.
A nicely structured program would look like (notice comments):
#include <stdio.h>
// Don't use magical numbers for constants in the program
// The use macros for this will suffice and look a ton cleaner
#define MAX_LENGTH 64
#define FMT_LENGTH "%63s"
// Our structure
struct database {
char name[MAX_LENGTH];
int number;
int roll;
};
int main(void) {
// You are here only creating single instances of struct
struct database s1, s2;
printf("Enter name, number and roll: ");
// Always check if the values are correctly assigned to their respective
// variables, if not, print error and exit (in this context)
if (scanf(FMT_LENGTH " %d %d", s1.name, &s1.number, &s1.roll) != 3) {
printf("error: One of the values are incorrectly assigned.\n");
return 1; // Exit Failure
}
// Same with s2
printf("Name: %s | Number: %d | Roll: %d\n", s1.name, s1.number, s1.roll);
return 0;
}