Programming Fundamentals

Check in week

Reminder: This week is a check-in week, so please make sure to stay around in the lab time for your one-on-one with one of your Tutors.

Part 0: Welcome & Assignment 1

Great job getting through Assignment 1 (or almost getting through if you are in a Monday class)!

Part 1: The parts of a pointer

In this section, tutors will lead a short revision section on pointers, and then walk through a demonstration simulating how pointers manipulate memory.

This tool will be used to further explore pointers:

What will happen when each of the following statements is executed (in order)?

int n = 42;
int *p;
int *q;
p = &n;
*p = 5;
*q = 17;
q = p;
*q = 8;

Fill in the values of each variable in the below visual at each point in the code execution.

          01: int n = 42;
          02: int *p;
          03: int *q;
          04: p = &n;
          05: *p = 5;
          06: *q = 17;
          07: q = p;
          08: *q = 8;

Type:

Name:

Value:

Note: Address lengths have been reduced for brevity.

Part 2: Coding with Functions and Pointers

Have a quick look at the following code:

#include <stdio.h>

void increment_time(int days, int hours, int minutes);

int main(void) {
    int days = 3;
    int hours = 4;
    int minutes = 59;

    increment_time(days, hours, minutes);

    printf("Current time: %d days, %d hours and %d minutes", days, hours, minutes);

    return 0;
}

// increments the time by 1 minute
void increment_time(int days, int hours, int minutes) {
    minutes++;
    if (minutes == 60) {
        minutes = 0;
        hours++;
    }

    if (hours == 24) {
        hours = 0;
        days++;
    }
}

Note that function increment_time doesn't seem to be working correctly.

Part 3: Struct pointers

Have a quick look at the following code which is slightly different from part 2 using a struct:

#include <stdio.h>

struct time {
    int days;
    int hours;
    int minutes;
};

void increment_time(struct time current_time);

int main(void) {

    struct time current_time;
    current_time.days = 3;
    current_time.hours = 4;
    current_time.minutes = 59;

    increment_time(current_time);

    printf("Current time: %d days, %d hours and %d minutes", 
        current_time.days, current_time.hours, current_time.minutes);

    return 0;
}

// increments the time by 1 minute
void increment_time(struct time current_time) {
    current_time.minutes++;
    if (current_time.minutes == 60) {
        current_time.minutes = 0;
        current_time.hours++;
    }

    if (current_time.hours == 24) {
        current_time.hours = 0;
        current_time.days++;
    }
}

Note that function increment_time in this example also doesn't seem to be working correctly.

Part 4: Malloc and Arrays

In this section we'll have a look at how we can create arrays using malloc

struct pet {
    int age;
    int weight;
    char name[100];
};

int main(void) {

    int i;
    double d;
    int array1[10];
    char array2[4];
    struct pet coco;
    struct pet class_pets[5];

}

Part 5: EOF Loops (Optional)

In this section, you'll be revising the different ways we can read input until EOF.

We'll be using this starter code:

#include <stdio.h>

#define MAX_LETTERS 100

int main (void) {

    char my_var;
    while (scanf(" %c", &my_var) == 1) {
        printf("Input: %c\n", my_var);
    }

    return 0;
}