APC-PRAC-041.c (1116B)
1 /* 2 Write a C program to find and print all twin prime pairs between 1 and n using nested loops. 3 (Twin primes are prime numbers having a difference of 2, like 11 and 13) 4 */ 5 /* Author: Amit Dutta, Date: 21-11-2025 */ 6 7 // This code has not been compiled. 8 // If you find any issues, please create a new issue on GitHub regarding them. 9 // Go to this link to create a new issue: https://github.com/notamitgamer/bsc/issues 10 11 #include <stdio.h> 12 #include <math.h> 13 14 int isPrime(int n) 15 { 16 if (n < 2) 17 return 0; 18 if (n == 2) 19 return 1; 20 if (n % 2 == 0) 21 return 0; 22 int i, temp = (int)sqrt(n); 23 for (i = 3; i <= temp; i += 2) 24 if (n % i == 0) 25 return 0; 26 return 1; 27 } 28 29 int main() 30 { 31 int n, i, count = 0; 32 printf("enter the n: "); 33 scanf("%d", &n); 34 printf("\nAll the twin numbers: "); 35 for (i = 1; i <= n - 2; i++) 36 { 37 if (isPrime(i)) 38 { 39 if (isPrime(i + 2)) 40 { 41 printf("(%d, %d) ", i, i + 2); 42 count++; 43 } 44 } 45 } 46 printf("\nCount; %d", count); 47 return 0; 48 }