BD-shell 1.0.0 released
Sunday, September 14th, 2008I'm very pleased to announce the final release of my tiny C Unix Shell. Every requirement has been satisfied. I hope I will find the time to expand it
http://bd-things.net/projects/bd-shell/
Posts Tagged ‘tiny c’
An example of mutual recursion using C
Tuesday, February 26th, 2008The first lecture of DSA was already interesting for me, I learned something about "Mutual Recursion" (when two procedures call each other). The pseudo-code example was about checking if a number is either even or odd.
Given that
- 0 is even
- N is even if n-1 is odd
- N is odd if n-1 is even
And the algorithm:
even INPUT: n – a natural number. OUTPUT: true if n is even; false otherwise odd(n) if n = 0 then return FALSE return even(n-1) even(n) if n = 0 then return TRUE else return odd(n-1)
I implemented a tiny C program which uses it:
#include <stdio.h>
int main (int argc, char const *argv[])
{
// set an integer number here
int number = 23945;
// if the number is odd (1 = TRUE)
if(odd(number)==1)
printf("%d is odd\n",number);
else
printf("%d is even\n",number);
return 0;
}
int main (int argc, char const *argv[])
{
// set an integer number here
int number = 23945;
// if the number is odd (1 = TRUE)
if(odd(number)==1)
printf("%d is odd\n",number);
else
printf("%d is even\n",number);
return 0;
}
// returns 0 if the given number becomes 0, so the given number is odd
// returns even(number - 1) elsewhere
int odd(int number){
if (number==0)
return 0;
else
return even(number-1);
}
// returns 0 if the given number becomes 0, so the given number is even
// returns odd(number - 1) elsewhere
int even(int number){
if(number==0)
return 1;
else
return odd(number-1);
}
Let's see if I can keep understanding things at DSA 
Sorting array elements with C language
Saturday, February 23rd, 2008UPDATE 17:19: it seems that the program I implemented today uses a kind of Bubble Sort algorithm, give it a try, it's quite interesting!
After 3 long days studying C, I think I've assimilated a good knowledge base for the incoming semester.
So there is a tiny C program that sorts the elements of a given integer array, using pointers:
Download the source code (well commented)
#include <stdio.h>
void sortArray(int *firstElement, int *lastElement);
void swapArrayElements(int *firstElement, int *secondElement);
void printArray(int array[], int arraySize);
void sortArray(int *firstElement, int *lastElement);
void swapArrayElements(int *firstElement, int *secondElement);
void printArray(int array[], int arraySize);
void sortArray(int *firstElement, int *lastElement){
int *currentElement = firstElement;
while (firstElement != lastElement){
while(currentElement != lastElement){
if(*currentElement < *firstElement){
swapArrayElements(currentElement,firstElement);
}
currentElement++;
}
firstElement++;
currentElement = firstElement;
}
}
void swapArrayElements(int *firstElement, int *secondElement){
int tmp;
tmp = *firstElement;
*firstElement = *secondElement;
*secondElement = tmp;
}
void printArray(int array[], int arraySize){
int counter = 0;
while(counter<arraySize){
printf("%d\n",array[counter]);
counter++;
}
}
int main (int argc, char *argv[]){
int array[] = {2929393,1,23239,-66,15,4,3,0,112,45,3,1000,19};
int arraySize = sizeof(array)/sizeof(array[0]);
int *firstElement = &array[0];
int *lastElement = firstElement + arraySize;
printf("-------------------------------------------------\n");
printf("Elements of the array:\n");
printf("-------------------------------------------------\n");
printArray(array,arraySize);
printf("-------------------------------------------------\n");
sortArray(firstElement,lastElement);
printf("Elements sorted:\n");
printf("-------------------------------------------------\n");
printArray(array,arraySize);
printf("-------------------------------------------------\n");
}
A better program should ask the user to input the array elements, and a better algorithm should not scan every array element n times, where n is the number of the elements.
But I wrote it just for fun and for learning C pointers. I will learn to do better in the Data Structures and Algorithms course in the next semester 