Printing prime or composite using For Loop in C++
This is a C++ program that prompts the user to input a number, and then determines whether the number is prime or composite. Here is a brief explanation of the program:
- The program declares four integer variables: i, n, a, and prime, and initializes prime to 0.
- The program prompts the user to input a number, and reads it from the standard input using the cin object.
- The program enters a for loop that iterates from 2 to i-1 inclusive, with a step of 1. In each iteration, the loop body is executed.
- In the loop body, the program checks if the current value of n divides i without leaving a remainder. If so, the variable prime is incremented by 1. This is because a prime number is only divisible by 1 and itself.
- After the loop terminates, the program checks the value of prime. If it is 0, then i is a prime number and the program outputs "This number is Prime". Otherwise, i is a composite number and the program outputs "This number is Composite".
- Finally, the program returns 0 to the operating system, indicating successful execution.
Source Code
#include<iostream>
using namespace std;
int main()
{
int i,n,a,prime=0;
cout<<"\nEnter the number:";
cin>>i;
for(n=2;n<i;n++)
{
if(i%n==0)
{
prime++;
}
}
if(prime==0)
{
cout<<"\nThis number is Prime";
}
else
{
cout<<"\nThis number is Composite";
}
return 0;
}
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Output
Enter the number:10
This number is Composite