Program 1
#include<stdio.h> int main(){ int num,i,count=0; printf("Enter a number: "); scanf("%d",&num); for(i=2;i<=num/2;i++){ if(num%i==0){ count++; break; } } if(count==0 && num!= 1) printf("%d is a prime number",num); else printf("%d is not a prime number",num); return 0; }
Result
Enter a number: 5 5 is a prime number
Program 2
#include<stdio.h> int main(){ int num,i,count; for(num = 1;num<=100;num++){ count = 0; for(i=2;i<=num/2;i++){ if(num%i==0){ count++; break; } } if(count==0 && num!= 1) printf("%d ",num); } return 0; }
Result
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
Program 3
#include<stdio.h> int main(){ int num,i,count,n; printf("Enter max range: "); scanf("%d",&n); for(num = 1;num<=n;num++){ count = 0; for(i=2;i<=num/2;i++){ if(num%i==0){ count++; break; } } if(count==0 && num!= 1) printf("%d ",num); } return 0; }
Result
Enter max range: 50 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47
Program 4
#include<stdio.h> int main(){ int num,i,count,min,max; printf("Enter min range: "); scanf("%d",&min); printf("Enter max range: "); scanf("%d",&max); num = min; while(num<=max){ count = 0; i=2; while(i<=num/2){ if(num%i==0){ count++; break; } i++; } if(count==0 && num!= 1) printf("%d ",num); num++; } return 0; }
Result
Enter min range: 50 Enter max range: 100 53 59 61 67 71 73 79 83 89 97
Program 5
#include<stdio.h> int main(){ int num,i,count,min,max; printf("Enter min range: "); scanf("%d",&min); printf("Enter max range: "); scanf("%d",&max); for(num = min;num<=max;num++){ count = 0; for(i=2;i<=num/2;i++){ if(num%i==0){ count++; break; } } if(count==0 && num!= 1) printf("%d ",num); } return 0; }
Result
Enter min range: 10 Enter max range: 50 11 13 17 19 23 29 31 37 41 43 47
Program 6
#include<stdio.h> int main(){ int num,i,count,sum=0; for(num = 1;num<=100;num++){ count = 0; for(i=2;i<=num/2;i++){ if(num%i==0){ count++; break; } } if(count==0 && num!= 1) sum = sum + num; } printf("Sum of prime numbers is: %d ",sum); return 0; }
Result
Sum of prime numbers is: 1060
Program 7
#include<stdio.h> int main(){ int num,i,count,min,max,sum=0; printf("Enter min range: "); scanf("%d",&min); printf("Enter max range: "); scanf("%d",&max); for(num = min;num<=max;num++){ count = 0; for(i=2;i<=num/2;i++){ if(num%i==0){ count++; break; } } if(count==0 && num!= 1) sum = sum + num; } printf("Sum of prime numbers is: %d ",sum); return 0; }
Result
Enter min range: 50 Enter max range: 100 Sum of prime numbers is: 732