/*
 * side_effects.c
 * CS 251 Lesson 6
 * Studies in the side effects of C statements
 */

// Compile with:
//      clang -o side_effects side_effects.c
//
// Run with:
//      ./side_effects

#include <stdio.h>

// GLOBALS!!
int a;
int b;

void f(int x)
{
    int a = 4;
    x += 1;
    printf("In f:      %d %d\n", a, x);
}

void g()
{
    a += 1;
    printf("In g:   a=%d\n", a);
}

void h(char *vals)
{
    vals[0] = 'X';
    printf("In h:     { %c %c %c %c }\n", vals[0], vals[1], vals[2], vals[3]);
}

int main()
{
    // First we'll play with some integers
    a = 10;
    b = a;
    b = 20;

    printf("/** TEST 1 **/\n");
    printf("%d, %d\n", a, b);

    // Now we'll look at function scope
    printf("\n/** TEST 2 **/\n");
    printf("Before f: %d %d\n", a, b);
    f(b);
    printf("After f:  %d %d\n", a, b);

    // How could we change a?
    printf("\n/** TEST 3 **/\n");
    printf("Before g: %d %d\n", a, b);
    g();
    printf("After g:  %d %d\n", a, b);

    // Okay, now what if we look at lists, not just ints?  (We'll use arrays.)

    printf("\n/** TEST 4 **/\n");
    char lst[4] = { 'a', 'b', 'c', 'd' };
    printf("Before h: { %c %c %c %c }\n", lst[0], lst[1], lst[2], lst[3]);
    h(lst);
    printf("After h:  { %c %c %c %c }\n", lst[0], lst[1], lst[2], lst[3]);

    return 0;
}