chore(CPlusPlus): add program to find prime number (#500)

Co-authored-by: Rahul Rajeev Pillai <66192267+Ashborn-SM@users.noreply.github.com>
Co-authored-by: Rahul Rajeev Pillai <66192267+Ashborn-SM@users.noreply.github.com>

algorithms/CPlusPlus/Maths/prime-number.cpp

@@ -0,0 +1,34 @@
+// It is a prime number program in c language.
+// it is used to check whether a given number is prime or not
+
+#include <iostream>	//header
+
+using namespace std;
+int main() { //main function
+  int num, i, a = 0; //define variable
+  cin >> num; //taking input from user
+
+  for (i = 2; i <= num / 2; i++) { //for loop started
+    if (num % i == 0) { //if condition
+      a++;
+    }
+  }
+  if (num < 2) {
+    a++;
+  }
+  if (a == 0) {
+    cout << "Prime"; // printing if the number is prime
+  } else {
+    cout << "Non-Prime"; // printing if the number is non-prime
+  }
+  return 0; // returning from main function
+}
+
+//	sample input   ||	sample output
+//	      1        ||        Nom-Prime
+//	      2        ||          Prime
+//            3        ||          Prime
+//	      4        ||        Non-Prime
+//	      5        || 	   Prime
+
+// time complexity of this program is O(n).

algorithms/CPlusPlus/README.md

@@ -130,6 +130,8 @@
 8. [Reverse digit of a number](Maths/reverse-digits.cpp)
 9. [Missing number](Maths/missing-number.cpp)
 10. [Factorial of a number](Maths/factorial.cpp)
+11. [Prime-number](Maths/prime-number.cpp)
+
 
 # Recursion