Please can anyone help in debugging this code to show if 13 is a prime number

Question

#include <iostream>
#include <cmath>
using namespace std;

int main ()
{
double a, b, num1, num2;
a = 13;
b = 1;
num1 = a/a;
num2 = a/b;
If (num1 ==b && num2 ==a) {
cout << "The value 13 is a prime number";
}
else {cout << "The value 13 is not a prime number"; }

return0;
}

Answer 1

your condition for checking prime number is kinda complex and wrong, I inputted a = 14 and its saying 14 is prime number.

Prime number condition:
A number divisible by only 1 and itself
2 is the only even prime number.

but according to your code.
a = 14
b = 1
num1 = a/a = 14/14 = 1
num2 = a/b = 14/1 = 14

if(num1==b && num2==a) is always true for non prime number.

Answer 2

There are some typos:
'If' should be 'if'
'return0' should be 'return 0'
...
And then, the test does not check if it is a prime number as the condition will always be true for all values of a...

Answer 3

#include <iostream>

using namespace std;

int main()
{
int x,d,c;
c=0;
cin>>x;
for(d=1;d<=x;d++){
if(x%d==0){
c++;
}
d++;
}

if(c==2){
cout<<"number is prime ";
}else{
cout<<"number is not prime ";
}
return 0;
}

Answer 4

Can anyone help with a c++ program to show if 13 is a prime number