check given number is prime number or not using c program | CTechnotips


Definition of prime number: 

A natural number greater than one has not any other divisors except 1 and itself. In other word we can say which has only two divisors 1 and number itself. For example: 5
Their divisors are 1 and 5.

Note: 2 is only even prime number. 

Logic for prime number in c
We will take a loop and divide number from 2 to number/2. If the number is not divisible by any of the numbers then we will print it as prime number.
Example of prime numbers : 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, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199 etc.

Code 1:

1. C program to determine prime number
2. Determining if a number is prime in c
3. C program to find given number is prime or not
#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;
}
Sample output:
Enter a number: 5
5 is a prime number

Code 2:

1. C program for prime numbers between 1 to 100
2. How to find prime numbers from 1 to 100 in c
3. How to print prime numbers from 1 to 100 in c
#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;
}
Output:
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

Code 3:

1. C program for prime numbers between 1 to n
2. C program to find prime numbers up to n
3. C program to list prime numbers
4. Write a c program to generate n prime numbers
5. C program to find n prime numbers
#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;
}
Sample output:
Enter max range: 50
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47
  
Code 4:

1. C program to find prime numbers using while loop
2. Wap to find prime numbers in c
3. Write a c program to generate prime number
4. How to get prime numbers in c
#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;
}
Sample output:
Enter min range: 50
Enter max range: 100
53 59 61 67 71 73 79 83 89 97

Code 5:

1. How to find out prime numbers in c programming
2. Display prime numbers in c
3. C program to find prime numbers between two numbers
4. C code to display prime numbers within a range
#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;
}
Sample output:
Enter min range: 10
Enter max range: 50
11 13 17 19 23 29 31 37 41 43 47

Code 6:

1. Sum of prime numbers from 1 to 100 in c
#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;
}
  
Output:
Sum of prime numbers is: 1060

Code 7:

1. C program to find sum of prime numbers

#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;
}
Sample output:
Enter min range: 50
Enter max range: 100

Sum of prime numbers is: 732

Code 8:

1. PRINT PRIME NUMBERS BETWEEN 1-300 USING BREAK AND CONTINUE IN C 

#include <math.h>
#include <stdio.h>
main(){
  int i, j;
  i = 1;
  while ( i < 300 ){
     j = 2;
     while ( j < sqrt(i) ){
         if ( i % j == 0 )
            break;
         else{
            ++j;
            continue;
         }
      }
      if ( j > sqrt(i) )
            printf("%d\t", i);
      ++i;
  }
  return 0;
}

3 comments:

Anonymous said...

VERY GOOD..

Chaitanya said...

#include
#include
#include

int main(int argc, char *argv[])
{
int num,loop,tL,again;
do
{
printf("enter number\n");
scanf("%d",&num);
tL=sqrt(num);
for(loop=2;loop<=tL;loop++)
{

if(num%loop==0)
{
printf("\tnumber is divisible by %d\n",loop);
if(num==loop)
{
printf("\t\t\t\tEVERY NUMBER IS DIVISIBLE BY ITSELF\n");
continue;
}
break;
}

if(num%loop)
{
printf("number is NOT divisible by %d\n",loop);

}

}
if(num%loop)
{
printf("\t\t\t\tNUMBER IS PRIME\n!");

}
printf("do you want to go again (1/2)\n");
scanf("%d",&again);
}while(again==1);
getch();
}

Arun Kumar said...

Nice code but instead of dividing the N with every number between 1 to N/2, we can just check till sqrt(N) is enough. You cam find this code here Check Prime number or not

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