Week 2 Code Examples

jake/control_flow.c

#include<stdio.h>

// this is a constant that sets MIN_AGE to 18
#define MIN_AGE 18

int main(void) {
    int age;
    printf("Enter your age: ");
    scanf("%d", &age);

    // check is age is valid
    if (age <= 0) {
        printf("That is invalid!\n");
    } else {
        // we know for a fact everythign here is a positive age!
        // age is 1 or higher

        // are you greater than 0 but less than 18
        if(age < MIN_AGE) {
            printf("You are too young (but valid!)! Get out\n");
        } else {
            printf("You are legal! Enjoy\n");
        }
    }
    return 0;
}

jake/counting.c

#include<stdio.h>

int main(void) {
    int number_of_lines = 5;
    int i = 0;

    while (i < number_of_lines) {
        printf("hey!\n");
        i = i + 1;
    }
}

jake/counting_scanning.c

#include<stdio.h>

int main(void) {
    int finished = 0;

    while (!finished) {
        printf("hey! Keep printing?\n");
        printf("(enter 1 if finished): ");
        
        scanf("%d", &finished);
    }

    printf("Program finishing up\n");
}

sasha/grid.c

// A while inside a while (tick tock)
// Demonstrating how you can put a while inside a while to print out a 
// grid of numbers
// Week 2, Lecture 4

/* Problem: Print out a grid of numbers that looks like this: 

1 2 3 4 5

*/

#include <stdio.h>

int main(void) {

    // 1. Initialise a loop control variable
    // int count = 1;
    int i = 0;
    int j = 1;
    int size;
    printf("What is the size of the square you want to print? ");
    scanf("%d", &size); 

    // 2. Test the condition of the size 
    while (i < size) {
        j = 1;
        while (j <= size) {
            printf("%d ", j);
            j++;
        }
        printf("\n");
        // 
        //3. Update the loop control variable
        // count++; // count = count + 1;
        i++; 
    }
    
    return 0;
}

sasha/pyramid.c

// A while inside a while (tick tock)
// Demonstrating how you can put a while inside a while to print out a 
// pyramid of numbers
// Week 2, Lecture 4


/* Problem: Print out a grid of numbers that looks like this: 
                    
1                    
1 2                
1 2 3               
1 2 3 4              
1 2 3 4 5              

*/

#include <stdio.h>

#define SIZE 5

int main(void) {

    int i = 1;

    while (i <= SIZE) {
        int j = 1;
        while (j <= i) {
            printf("%d ", j);
            j++;
        }
        printf("\n");
        i++;
    }


    return 0;
}

sasha/while_count.c

// This program will demonstrate a simple while loop
// Week 2 Lecture 4

#include <stdio.h>

int main(void) {
    // 1. Initiliase the loop counter before the loop (before the loop!)
    int counter = 0;
    // 2. Test for the condition in the loop (the loop itself)
    while (counter < 10) {

        printf("Loop number %d - here we go!\n", counter); 
        // 3. Update the loop counter (inside the loop!)
        counter++; // counter = counter + 1; 
    }
    
    // What will the counter be when I exit out of the loop? COUNTER = 10


    return 0;
}

sasha/while_infinite.c