mirror of https://github.com/TheAlgorithms/C
36 lines
569 B
C
36 lines
569 B
C
#include <math.h>
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#include <stdio.h>
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int isPrime(int x)
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{
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if (x == 2)
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{
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return 1;
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}
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if (x < 2 || x % 2 == 0)
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{
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return 0;
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}
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double squareRoot = sqrt(x);
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for (int i = 3; i <= squareRoot; i += 2)
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{
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if (x % i == 0)
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return 0;
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}
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return 1;
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}
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int main()
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{
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int a;
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printf("Input a number to see if it is a prime number:\n");
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scanf("%d", &a);
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if (isPrime(a))
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printf("%d is a prime number.\n", a);
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else
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printf("%d is not a prime number.\n", a);
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return 0;
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}
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