pc006.c (896B)
1 /* Prime number check */ 2 3 #include <stdio.h> 4 #include <math.h> 5 6 int main() 7 { 8 int num, i, temp; 9 printf("Enter the number : "); 10 if(scanf("%d", &num) != 1) { 11 printf("Only postive number allowed."); 12 return 1; 13 } 14 if(num <= 0) { 15 printf("\nOnly potive number are allowed."); 16 return 1; 17 } 18 if(num == 1) { 19 printf("\nInput 1 is not a prime number."); 20 return 0; 21 } 22 if(num == 2) { 23 printf("\nInput 2 is a prime number."); 24 return 0; 25 } 26 if(num % 2 == 0) { 27 printf("\nInput %d is not a prime number.", num); 28 return 0; 29 } 30 temp = (int)sqrt(num); 31 for (i = 3; i <= temp; i += 2) 32 { 33 if (num % i == 0) 34 { 35 printf("\nInput %d is not a prime number.", num); 36 return 0; 37 } 38 } 39 printf("\nInput %d is a prime number.", num); 40 return 0; 41 }