Question

Multithreaded program that outputs prime numbers in c

Answer 1

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#include <iostream>

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using namespace std;

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int main(){

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clock_t start = clock();

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 int count = 0;

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 for(int i = 2; i < 5000000; i++){

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   bool prime = true;

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   for(int j = 2; j*j <= i; j++){

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     if(i % j == 0){

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       prime = false;

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       break;

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     }

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   }

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   if(prime){

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     count++;

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     if(count <= 100)

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       cout << i << " ";

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     else if(count > 348413)

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       cout << i << " ";

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   }

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 }

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 clock_t end = clock();

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 cout << "\n\nThere are " << count << " primes under 5,000,000." << endl;

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 cout << "Program took " << (double)(end  - start) / CLOCKS_PER_SEC << "seconds." << endl;

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}