grade.c

#include <stdio.h>
#include <stdlib.h>

/**
 * grade1.c
 *
 * This program will allocate memory for an integer on the stack, and
 * demonstrate how C treats values passed by value as opposed to by reference.
 */

int finalGradeValue (int grade, int bonus);  //grade passed by value
int finalGradeReference (int* grade, int bonus);  //grade passed by reference


int main() {

    int grade = 45;

    finalGradeValue (grade, 5);  // passed value not modified
    printf ("Your final mark is %d. ", grade);
    puts (grade < 50 ? "You failed!" : "You passed!");

    finalGradeReference (&grade, 5);  // passed value modified, notice '&'
    printf ("Your final mark is %d. ", grade);
    puts (grade < 50 ? "You failed!" : "You passed!");

    return 0;
}


int finalGradeValue (int grade, int bonus) {
    grade = grade + bonus;
    return grade;
}

int finalGradeReference (int* grade, int bonus) {
    *grade = *grade + bonus;
    return *grade;
}