PASS Week 14: Structs and Typedef

Here is another pastebin link that contains examples of structs!
I separated the pastebins because the examples have quite a few lines
(The code itself isn't long, I just have a lot of whitespace in my code)

https://pastebin.com/L0aV2Tu7









WARM-UP PROBLEM

Below is an incomplete program that uses a struct STUDENT that contains information about
a student. The struct itself is programmed, and nothing else needs to be added. Your goal
is to declare a STUDENT struct in main and assign the values already in main to the equivalent
variables in the struct.


#include <stdio.h>
#include <string.h>

#define ID_SZ 10 //ID Size
#define NM_SZ 25 //Name Size

struct STUDENT{
	char id[ID_SZ];
	char fName[NM_SZ];
	double GPA;
};

int main(void) {
	double gpa = 98.3;
	char nameIn[NM_SZ] = "Larry";
	char idIn[ID_SZ] = "LS1234";

	/* Declare Student struct here */

	/* Assign ID in the struct here */
	/* Assign First Name in the struct here */
	/* Assign GPA in the struct here */

	printf("Student %s ID:%s has a %.2lf GPA\n", /* struct name, ID, and GPA here */ );
	printf("\n");

	return 0;
}



















PROBLEM #1: Creating structs and an Array of Structs

This program will involve creating a struct called CAR with two data fields: Brand and Vehicle ID.
Then create an array of CAR structs with a size of 4. The car will have a brand
(Ford, Chevy, KIA, Toyota etc.) and will have a RANDOMLY GENERATED VIN or Vehicle Id Number (4 digits in length).
Create a user defined function to load the array by asking the user for the input and then storing it. It returns void.
Then create a second user function used to print out the array of cars and their details. It returns void.

The challenge here is how to pass the array of CARs to each function.
(OPTIONAL Challenge: Make sure the vehicle IDs are UNIQUE and have no duplicates)


SAMPLE OUTPUT:

Enter a brand: Ford
Enter a brand: Honda
Enter a brand: Toyota
Enter a brand: Mitsubishi

Car 1 has Brand: Ford ID: 5116
Car 2 has Brand: Honda ID: 9966
Car 3 has Brand: Toyota ID: 6543
Car 4 has Brand: Mitsubishi ID: 4452










PROBLEM #2: Using Typedef

Using the program from the previous problem, use typedef to make CAR a type. You can now
pass the array of CAR without the struct keyword and you can use a pointer to a type now too.















Problem #3: Using Pointers to Structs

Previously, you saw how an array of structs can be passed to functions as a pointer because the
name of an array acts like a pointer but is still an array. Therefore, we could still use the direct
operator to access members in the structs in the array. Take the incomplete program given
below and add the missing code to return the result of raising x to the power of y by accessing
the values form the ptr to the struct SAMPLE. The function PowerUpWrong is used to
demonstrate how not to do this. When dealing with a pointer to a struct, you access members
using the indirect selection operator ‘->’. Look for “/*your code here*/”.
Skeleton Code missing function code below:

#include <stdio.h>
#include <math.h>

typedef struct{
int x;
int y;
int res;
} SAMPLE;

void PowerUp( /* your code here */ );
void PowerUpWrong(SAMPLE);

int main(void) {
    SAMPLE sample1 = {2, 5, 0}; //Initializes fields/members
    SAMPLE* samplePtr;
    samplePtr = &sample1; //Create a pointer to the struct

    PowerUpWrong(sample1);
    printf("The incorrect result is %d\n", sample1.res);

    PowerUp(samplePtr);
    printf("%d raised to the power of %d is: %d\n", sample1.x, samplePtr->y, sample1.res);
    //Note the use of both the indirect and direct selection operators

    return 0;
}

void PowerUpWrong(SAMPLE ptr){
    int result = 0;
    ptr.res = (int)pow(ptr.x, ptr.y);

    return;
}

void PowerUp( /* your code here */ ){
    int result = 0;
    result = (int)pow( /* your code here */ );
    /* your code here */ = result;

    return;
}




















PROBLEM #4

Construct a program using typedef. The term scalar is used to denote a quantity having magnitude but
not any direction (ascending or descending). A vector is like a scalar but has direction. A sorted list of
numbers could be referred to as a vector. The dot product or scalar product is an algebraic operation
where two equally sized sequences of numbers are computed to a single number. Your program should
define a value N with a value of 4. Next, declare a new type of scalar of type double and name it SCALAR.
Now create a second new type pf SCALAR that is called a VECTOR and give it a size of N. In main, declare
and define two new VECTORs X and Y. Initialize them with any 4 values. Create a user defined function
called Dot_Product that takes two VECTORs and returns a SCALAR value back to the caller. In main call
the new function and print out the computed value. Sample output is shown below

SAMPLE OUTPUT:

The vector:  2.000000  5.400000  6.000000  9.000000
The vector:  4.200000  5.400000  6.700000  7.000000
The Dot Product of X and Y is:     140.76