Write a C program to count all the composite numbers in an array, In this C program example, we will see how to count composite numbers in an array.

What is a composite number?

Those number which has divided by more than two numbers, or the number give more two factorial, or not a prime number is known as a composite number. for example 4= 4/1=0, 4/2=0, 4/4=0, 4 is divided by 3 numbers that is 1,2,and 4.

Sample input

enter the size of an array: 4

enter elements:

Sample output

total composite number is: 3

Algorithm to count all the composite numbers in an array

Declare one array and three variables.
Take two inputs first for the size of an array and another for taking elements in the array.
Take two for loop, one is for input and another for loop is for to give logic and condition.
Take if, else if and if statement.
Print with an appropriate message.

C program to count all the composite numbers in an array

#include<stdio.h>
void main (){
    int i,n,a[100],count=0;
    printf("enter size:");
    scanf("%d",&n);
    printf("enter elements\n");
    for(i=0;i<n;i++){
    	scanf("%d",&a[i]);
    }
    for(i=0;i<n;i++){
       if(a[i]==2){
     	 continue;
       }       
        else if(a[i]%2==0){
         count++;
        }
    }
        if(count>2){    
        }
       printf("total composite number are: %d",count);
 }

Explanation of this C program

Step 1: Start.

Step 2: Create a header file and include the library on it.

Step 3: Create void main function.

Step 4: Declare one array and three variables.

Step 5: Create two inputs one is for the size of an array and another for taking elements in an array to create an input with help of scanf.

Step 6: Create two for loop first one for input of element and the second one for logic and conditon to count composite number.

Step 7: In for loop create if, and else if statement for logic :

– condition of for loop = (i=0;i<n;i++),

– condition of if statement = (a[i]==2) (to continue without two because two is aa prime number),

– condition of else if statement = (a[i]%2==0) (and increment of count++ to cheak next number after incriment).

Step 8: After for loop create a if statement, and the condition is “count>2” to print the number which is divide by moe than two number.

Step 9: Print a appropiate message with the help of printf and count.

Step 10: End.

Output of this C program

In this way, we learned how to write a C program to count all the composite numbers in an array