Writing a function to check whether an integer is a power of some other integer

int Solution::isPower(int A) {
    long double a,b;
   // cout<<a;
    if(A==1)
    {
        return 1;
    }
    for(float i=2;i<=A;i++)
    {
         b=1/i;
         //cout<<i<<endl;
         a=pow(A,b);
         //cout<<a<<endl<<(int)a<<endl;
         if((int)a == a)
         {
             return 1;
         }
    }
    return 0;
}

Even when int(a) is equals to a ,it is not returning 1.The problem is because of using long double type number.But when i use float type then it does not work for large numbers.