/* Copyright (c) 2020, Dive into Systems, LLC (https://diveintosystems.org/)
 * This file shows examples of defining and calling C functions.
 * It also demonstrates using scanf().
 */

#include <stdio.h>

/* This is an example of a FUNCTION PROTOTYPE.  It specifies just the type
 * information for a function (the function's name, return type, and parameter
 * list). A prototype is used when code in main wants to call the function
 * before its full definition appears in the file. */
int max(int n1, int n2);

/* A prototype for another function.  void is the return type of a function
 * that does not return a value */
void print_table(int start, int stop);

/* All C programs must have a main function.  This function defines what the
 * program does when it begins executing, and it's typically used to organize
 * the big-picture behavior of the program. */
int main(void) {
    int x, y, z;

    printf("This program will operate over two int values.\n");

    printf("Enter the first value: ");
    scanf("%d", &x);

    printf("Enter the second value: ");
    scanf("%d", &y);

    z = max(x,y);

    printf("The larger of %d and %d is %d\n", x, y, z);

    print_table(x, z);

    return 0;
}

/* This is an example of a FUNCTION DEFINITION.  It specifies not only the
 * function name and type, but it also fully defines the code of its body.
 * (Notice, and emulate, the complete function comment!) */

/* Computes the max of two integer values.
 *   n1: the first value
 *   n2: the other value
 *   returns: the larger of n1 and n2
 */
int max(int n1, int n2)  {
    int result;

    result = n1;

    if (n2 > n1) {
        result = n2;
    }

    return result;
}

/* prints out the squares from start to stop
 *   start: the begining of the range
 *   stop: the end of the range
 */
void print_table(int start, int stop) {
    int i;

    for (i = start; i <= stop; i++) {
        printf("%d\t",i*i);
    }

    printf("\n");
}