Write a C program to count the prime numbers in an array, In this C program example, we will learn Algorithm and C Code to count the prime numbers in an array.

Algorithm to count  the  prime numbers in an array

• Declare the main method
• Take array 
• Check for prime number
• Count the prime number    

C program to count the prime number in an array

#include<stdio.h>
void main(){
   int arr[100],i,a,j,b,count=0;
   printf("Enter size of an array:");
   scanf("%d",&a);
   printf("Enter array elements:");
   for (i=0;i<a;i++){
       scanf("%d",&arr[i]);
   }
   printf("All prime list is:");
   for(i=0;i<a;i++){
       j=2;
       b=1;
       while(j<arr[i]){
           if(arr[i]%j==0){
               b=0;
               break;
           }
           j++;
       }
       if(b==1){
       	count=count+1;
        printf("%d ",arr[i]);
       }
   }
    printf("\nthe total prime number is %d ",count);
}

Sample Input

10,13,21,27,19

Sample Output

The prime number is 13,19

The total prime number is 2

Explanation of this C program

Step 1 importing the library

Step 2 declare the main method using the void as its return type

Step 3 declare the variable and array

Step 4 command for the user to give size

Step 5 using the scanf method to take input

Step 6 command for user

Step 7, Step 8, Step 9 for loop to take input from user using scanf method and then closing the scope

Step 10 command for user

Step 11 for loop to access elements one by one

Step 12, Step 13 intialize the variable

Step 14  using a while loop to run the logic again and again

Step 15 checking the element whether it is greater than “j”  the variable is declared

Step 16 if the condition satisfies the expression we update the variable “b” to  0

Step 17   break the condition

Step 18 closing the scope

Step 19 increment the “j” variable

Step 20 closing the scope of the while loop

Step 21 now the variable we updated before, here  we check whether a variable is equal to 1

Step 22 increment in count variable to count the prime number

Step 23 print the element

Step24, Step 25 closing the scopes of other variables

Step 26 print the total prime number present in the array

Closing the loop

Output

In this blog, we learned how to create an array, find the prime number and then count them all