/**
*
*
* A description of the program: This program is responsible for carrying out the collatz sequence
* while utilizing two fork() functions. If the number is odd, the next number in the sequence
* would be 3n+1. If even, the next number would be n/2. The calculations of the sequence will continue
* until the number 1 is achieved. The first Child process utilizes the fork() function while the second Child
* process also utilizes the same function but computes the collatz sequence with the initial number plus six (6).
*
* Task 2: From analyzing the behaviors of this program, we can conclude that the first child, which
* is the one forked first, always finished before the second child, which is forked last. In my opinion,
* one can notice that data in this program operates in a first in, first out order.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
/** This method is responsible for: accepting two integer values, assigning the numeric values
* to the necessary variables, and computing the collatz sequence.
*/
void collatzConjecture(int number, int childNum) {
printf("From Child%d, pid=%d: number=%d\n", childNum, getpid(), number);
while(number != 1){
if (number % 2 == 0) {
number = number / 2;
} else {
number = 3 * number + 1;
}
printf("From Child%d: number=%d\n", childNum, number);
}
printf("From Child%d, pid=%d: I'm done!\n", childNum, getpid());
}
//main method
int main(){
//integer variable declared to store user input
int number = 0;
//two child process variables declared
pid_t child1, child2;
//promtps user to enter a number
printf("Please enter a number: ");
scanf("%d", &number);
//if the number entered is less than 0 or more than 40, an error message will be outputted
if(number >= 40 || number <= 0){
printf("This is an invalid number.");
return 1;
}
//outputs the number inputted
printf("collatz %d\n", number);
printf("This is the Parent waiting!\n");
//this is the first child, which will be forked first
child1 = fork();
//the method which computes the collatz conjecture is called
if(child1 == 0) {
collatzConjecture(number, 1);
exit(0);
}
wait(NULL);
//this is the second child, which will be forked last
child2 = fork();
//the method which computes the collatz conjecture is called
if(child2 == 0) {
collatzConjecture(number + 6, 2);
exit(0);
}
wait(NULL);
//After both children are forked, the program will let the user know when it is complete.
printf("All my Children Complete\n");
//the program was successfully completed
return 0;
}
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C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.
When ever you want to perform a set of operations based on a condition if-else is used.
if(conditional-expression) {
// code
} else {
// code
}
You can also use if-else for nested Ifs and if-else-if ladder when multiple conditions are to be performed on a single variable.
Switch is an alternative to if-else-if ladder.
switch(conditional-expression) {
case value1:
// code
break; // optional
case value2:
// code
break; // optional
...
default:
// code to be executed when all the above cases are not matched;
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement){
// code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while(condition) {
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (condition);
Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.
data-type array-name[size];
data-type array-name[size][size];
Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.
Two types of functions are present in C
Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,
User defined functions are the ones which are written by the programmer based on the requirement.
return_type function_name(parameters);
function_name (parameters)
return_type function_name(parameters) {
//code
}