Countdown

countdown.c

/* This is an example taken from a book, one day I might need to reference this so I thought I would save it, 
it uses many different techniques in c such as:
  - adding modules
  - create global variables using constsants and local variables inside functions
  - setting up prototyes for functions
  - defining different types such as long int, char
  - loops inside functions 
  - different style of comments 
  - break out of loop
  - if statements */

#include <stdio.h>      //  Include Standard Input Output Module
#include <stdio_ext.h>  //  Inserted module to be able to run __fpurge function

#define COUNT 50000000  //  Create a constant(a variable that never changes) called COUNT
void dropTakeoff(void); //  Prototype the dropTakeoff function
void delay(void);       //  Protoype the delay function

int launches;           //  Create a global integer variable called launches

/******************* Main Function **************************/
int main()              //  set first function as an integer

{

char x;                 //  set x as a character type
launches=0;

for(;;)                 // A recurring loop
    {

    printf("Press any key to start the Space Ship Countdown: ");    
    x=getchar();        //  prompt terminal and assign it to x
    __fpurge(stdin);    // This clears extra characters, otherwise will run twice
    if(x=='~')          // If the value of x is equal to the character ~
    {
        break;          // We break out of the loop if the statement is true
        printf("Thanks for playing\n");
    }        
        
    dropTakeoff();      //  Initiate the function DropTakeOff
    printf("The current launches are set to %d\n",launches);    
    // Formatted print, that prints value of x as an integer.
        
    }
return(0);


}
/***************** End of Main *****************************/

void dropTakeoff()      //  enter details of function dropTakeoff
{
    int x;              // set a local variable x as an integer
    for(x=10;x>1;x--)   // create a loop that starts with 10 and decrements
    {
        printf("counting down %d \n",x);    // While the loops is not true, print and delay
        delay();                            // Initiate the delay function
    }
    launches++;
    puts("  HOUSTON WE HAVE TAKEOFF!");     // Once function is true, print the following
}

void delay()            // enter details of function delay
{
    long int x;         // set a local variable x with a long integer type
    for(x=0;x<COUNT;x++)// create a loop, that sets x as 0, then increment until value is equal to COUNT
    ;                   // Needed as part of a loop to iterate
}

/* Another script that explains passing arguments from functions
#include <stdio.h>
void graph(int count);

int main()
{
        int value;
        value = 2;

        while(value<=64)  // While the value is less than 64, loop through the function graph.
                          // We will also pass on value to the argument.
        {
                graph(value);
                printf("Value is %d\n",value);
                value*=2;
        }
        return(0);
}

void graph(int count)
{
// This function called graph, increments by one, until it is less than count
// This (int count) is an argument. The argument is provided by value.
// So it will put those characters
        int x;
        for(x=0;x<count;x++)
        printf("*");
        printf("\n");
}
*/

/*************************************************************************
Another script which passes arguments the difference is that we return a value (which was calculated using user inputted info 
from the scanf function which is in main.

#include <stdio.h>

int main()
{

        float convert(float f);

        int main()
        {
                float temp_f,temp_c;                    // create two floats    
                printf("Temperature in Fahrenheit: ");  // Print something
                scanf("%f",&temp_f);                    // store user input into temp_f (its a float so we use &
                temp_c = convert(temp_f);               /* we pass the (user entered variable into an argument against the convert function 
                                                        and assign this operation against the variable temp_c */
                printf("%.1fF is %.fC\n",temp_f,temp_c); // display the variables before and after the conversion
        }

        float convert(float f);                         // Initate the function
        {
                float t;                                // create another float var called
                t = (f -32) / 1.8;                      /* This basically means that t is equal to (calculation)
                                                        the important part is that the f is the argument, that gets its value from the main
                                                        function, i.e temp_c = convert(temp_f) */
                return(t)                               // We return all this from the variable t
        }

}

*///////////////////////////////////////////////////////////////////////////////////////
/* Stopping a function with return

  #include <stdio.h>

void limit(int stop);

int main()
{
        int s;  // set up s as a var.

        printf(" Countdown from a value between (0-100): ");
        scanf("%d",&s); // have the var be decided by user input 
        limit(s);       // call the function limit and pass an argument (which is user input)
        return(0);
}

void limit(int stop)   // we setup the function called limit, with an integer called stop
{
        int x;

        for(x=0;x<=100;x++)  // we loop until x is less than 100 but x will be the called from the scanf in main()
        {
                printf("%d ",x); // we print each iteration of x
                if(x==stop)      // if the int stop matches with the value of x, we return (like a break) 
                {
                        puts("You won!");
                        return;
                }
        }
        puts("i won");
}
*/
  
  /* Looping through an array
#include <stdio.h>
#include <stdlib.h>

int main()
{
    int highscore[4];   //We setup an array that can hold 4 values
    int x;

    for(x=0;x<4;x++)    //Loop through 4 runs
    {
        printf("Your #%d score: ",x+1); // in the loop, print the number of array  that equals 1 x = (0+1 = 1)
        scanf("%d",&highscore[x]);      // in the loop, ask users to enter all entries
    }

    puts("Here are your high scores");
    for(x=0;x<4;x++)    // Loop through 4 runs
        printf("#%d %d\n",x+1,highscore[x]);     // print the number of the array and they highscore (of each array)
    return(0);
}
*/