Accepting larger numbers with decimal values in C - c

Question

I'm writing a code that allows the user to add employees by ID, age and salary however, for salary I'm not sure what value to use in order to scanf and printf a number such as 78950.86. I used double for SALARY because there are more values to hold and I've tried playing around with the printf and scanf for this variable, but it I either get segmentation faults or random numbers. Here's my code:
#include <stdio.h>
#define SIZE 2
// Define Number of Employees "SIZE" to be 2
struct Employee{
int ID;
int AGE;
double SALARY;
};
//Declare Struct Employee
/* main program */
int main(void) {
int option = 0;
int i;
struct Employee emp[SIZE];
printf("---=== EMPLOYEE DATA ===---\n\n");
// Declare a struct Employee array "emp" with SIZE elements
// and initialize all elements to zero
do {
// Print the option list
printf("1. Display Employee Information\n");
printf("2. Add Employee\n");
printf("0. Exit\n\n");
printf("Please select from the above options: ");
// Capture input to option variable
scanf("%d",&option);
printf("\n");
switch (option) {
case 0: // Exit the program
break;
case 1: // Display Employee Data
// #IN-LAB
printf("EMP ID EMP AGE EMP SALARY\n");
printf("====== ======= ==========\n");
//Use "%6d%9d%11.21f" formatting in a
//printf statement to display
//employee id, age and salary of
//all employees using a loop construct
for(i=0; i<SIZE; i++) {
printf("%d %d %11.2lf", emp[i].ID, emp[i].AGE, emp[i].SALARY);
}
//The loop construct will be run for SIZE times
//and will only display Employee data
//where the EmployeeID is > 0
break;
case 2: //Adding Employee
// #IN-LAB
printf("Adding Employee\n");
printf("===============\n");
for(i=0;i<SIZE;i++) {
printf("\nEnter employee ID: ");
scanf ("%d", &emp[i].ID);
printf("\nEnter employee Age: ");
scanf ("%d", &emp[i].AGE);
printf("\nEnter employee Salary: ");
scanf ("%11lf", &emp[i].SALARY);
}
//Check for limits on the array and add employee
//data accordingly
break;
default:
printf("ERROR: Incorrect Option: Try Again\n\n");
}
} while (option!= 0);
return 0;
}

Answer 1

Your format strings are using %ld.%02d when dealing with a double, which says to treat it as 2 integers separated by a period (which should have generated warnings). Fix the string to properly indicate one double, or if (as #MalcomMcLean suggests) you want to keep dollars and cents separately, use a different field/variable for each.

Answer 2

"I'm not sure what value to use in order to scanf and printf a number such as 78950.86."
Generally speaking, Salaries are not really "Large Numbers", in the world of Coding(or C data types, to be precise). For the example you have quoted even a single precision float data type will be sufficient. (Search for "max finite positive value in single precision" in the pagehttps://en.m.wikipedia.org/wiki/Single-precision_floating-point_format)
So the double data type you used is more than sufficient for the said purpose. As rightly pointed out by Scott, the segmentation faults are being caused because your format string suggests 2 data parameters, when there is only 1 double data type variable.
My opinion would be not to store salary data as separate dollars and cents. From the employer's perspective these cents are going to add up to dollars and they will eventually be merged with the dollar data, making your summation algorithm complicated.
In conclusion, you can use a double data type for salary variable. When printing salary, you can use "%.2f" in the format string. When using scanf to get salary in normal fixed point notation, you can use "%lf" in the format string.