Python competiton - Printable Version

Code:

//Include standard input-output.

#include <stdio.h>

//Function to check, whether the provided number is a prime, if it is, returns 0.

int start(int a)

{

 int i;

 for(i=2;i<(a/2)+1;i++)

 {

 if(a%i==0)

 return 1;

 }

 return 0;

}

//My lovely main function.

int main()

{

//Lets the user know the program is online.

printf("Starting...\n");

//Declare variables

int l,i,n,d,a;

//Ask for a number.

printf("Please enter your number: ");

scanf("%d",&d);

//Negativity check.

if(d<0)

{

 printf("The number you provided is negative and can't be achieved via multiplus of two positive numbers.\n");

 getchar();

 getchar();

 return 0;

}

i=2;

n=0;

//Find out how many primes there are from 0 to the number provided

while(i<d/2)

{

 if(start(i)==0)

 {

  n++;

  i++;

 } else {

 i++;

 }

}

//How many primes you need to find the number provided.

l=n;

//An array large enough, to hold the primes.

int primes[l];

//The first prime is 2, ergo i=2 at kickoff.

i=2;

n=0;

//While the array is not filled with primes...

while(n<=l)

{

//Find primes. If i is a prime, stick it in the array.

 if(start(i)==0)

 {primes[n]=i;

 n++;

 i++;}

 else

//If it isn't, keep searching.

 {i++;}

}

//Notify of the results, how many primes were calculated, etc.

printf("Done calculating the first %d primes into an array.\n",(l+1));

printf("The last calulated prime is %d.\n",primes[l]);

printf("Searching now...\n");

//Check if the provided number can be produced by multiplying numbers from the array, which holds the primes.

for(a=0;a<n;a++)

{

 for(i=0;i<n;i++)

 if(primes[a]*primes[i]==d)

 {

 //If yes, print out the numbers.

 printf("Gotcha, your primes are %d and %d!",primes[a],primes[i]);

 getchar();

 getchar();

 return 0;

 }

}

//Check, if the provided number is a prime on itself, if it's not achievable by multiplying other primes.

if(start(d)==0)

{

    printf("Provided number is a prime on itself and is not achiavable via multiplus of other primes.\n");

    getchar();

    getchar();

    return 0;

}

//If not, be sad. =(

printf("No primes identified.");

getchar();

getchar();

return 0;

}

//Written by Etheryte, released to the free world.

Code:

//Include standard input-output.

#include <stdio.h>

//Function to check, whether the provided number is a prime, if it is, returns 0.

int start(int a)

{

 int i;

 for(i=2;i<(a/2)+1;i++)

 {

 if(a%i==0)

 return 1;

 }

 return 0;

}

//My lovely main function.

int main()

{

//Lets the user know the program is online.

printf("Starting...\n");

//Declare variables

int l,i,n,d,a;

//Ask for a number.

printf("Please enter your number: ");

scanf("%d",&d);

//Negativity check.

if(d<0)

{

 printf("The number you provided is negative and can't be achieved via multiplus of two positive numbers.\n");

 getchar();

 getchar();

 return 0;

}

//Check, if the provided number is a prime on itself, if it's not achievable by multiplying other primes.

if(start(d)==0)

{

    printf("Provided number is a prime on itself and is not achiavable via multiplus of other primes.\n");

    getchar();

    getchar();

    return 0;

}

//Check, if the provided number can be divided by 10.

if(d%10==0&&d!=10)

{

printf("No primes identified. (Number divides by 10.)");

getchar();

getchar();

return 0;

}

i=2;

n=0;

//Find out how many primes there are from 0 to the number provided

while(i<d/2)

{

 if(start(i)==0)

 {

  n++;

  i++;

 } else {

 i++;

 }

}

//How many primes you need to find the number provided.

l=n;

//An array large enough, to hold the primes.

int primes[l];

//The first prime is 2, ergo i=2 at kickoff.

i=2;

n=0;

//While the array is not filled with primes...

while(n<=l)

{

//Find primes. If i is a prime, stick it in the array.

 if(start(i)==0)

 {primes[n]=i;

 n++;

 i++;}

 else

//If it isn't, keep searching.

 {i++;}

}

//Notify of the results, how many primes were calculated, etc.

printf("Done calculating the first %d primes into an array.\n",(l+1));

printf("The last calulated prime is %d.\n",primes[l]);

printf("Searching now...\n");

//Check if the provided number can be produced by multiplying numbers from the array, which holds the primes.

for(a=0;a<n;a++)

{

 for(i=0;i<n;i++)

 if(primes[a]*primes[i]==d)

 {

 //If yes, print out the numbers.

 printf("Gotcha, your primes are %d and %d!",primes[a],primes[i]);

 getchar();

 getchar();

 return 0;

 }

}

//If not, be sad. =(

printf("No primes identified. (Via calculations.)");

getchar();

getchar();

return 0;

}

//Written by Etheryte, released to the free world.