can you please help what is wrong in my code

#include
#include
using namespace std;

int main()
{
float a, b, x, k, N;
cin>>a>>b>>x;
if ((sqrt(ab))!=0)
{
k=(pow(a, 2)+b
cos(x))/(sqrt(ab));
if ((exp(a
x)+pow(cos, 2)*pow(x, 3)+k)!=0)
{
N=(a+pow(sin, 2)xb+pow(a, 2)sqrt(b))/(exp(ax)+pow(cos, 2)*pow(x, 3)+k);
cout<<"N="<<N;
}
else cout<<"ERROR:/0";
}
else cout<<"ERROR:/0";
return 0;
}

The expectation that there's a "cout"?

And the fact that you've posted the same question TWICE.

That's an easy one. It's not Arduino code.

Steve

Arduino doesn't use C language. It is similar though.

See: Arduino Reference - Arduino Reference

Are you using the IDE? If you open a new file, you get

void setup() {

}

void loop() {

}

You insert your code inside the appropriate loop.

DaleScott:
Arduino doesn't use C language.

C doesn't have cin/cout either.

It's C++.

Please remember to use code tags when posting code.

    k = (pow(a, 2) + b * cos(x)) / (sqrt(a * b));
    if ((exp(a * x) + pow(cos, 2)*pow(x, 3) + k) != 0)
    {
      N = (a + pow(sin, 2) * x * b + pow(a, 2) * sqrt(b)) / (exp(a * x) + pow(cos, 2) * pow(x, 3) + k);
      cout << "N=" << N;

"pow(cos, 2)"?!? cos() is a function. If you don't give it an argument list you are getting the address of the function. Squaring the address of a function is unlikely to produce the desired result. Perhaps you meant "pow(cos(x), 2)"

This version compiles. I don't know if it will do what you want. What DO you want?

int main()
{
  init();
  Serial.begin(115200);
  float a, b, x, k, N;
  while (!Serial.available())
  {}


  a = Serial.parseFloat();
  b = Serial.parseFloat();
  x = Serial.parseFloat();


  if ((sqrt(a * b)) != 0)
  {
    k = (pow(a, 2) + b * cos(x)) / (sqrt(a * b));
    if ((exp(a * x) + pow(cos(x), 2)*pow(x, 3) + k) != 0)
    {
      N = (a + pow(sin(x), 2) * x * b + pow(a, 2) * sqrt(b)) / (exp(a * x) + pow(cos(x), 2) * pow(x, 3) + k);
      Serial.print("N=");
      Serial.println(N);
    }
    else
    {
      Serial.println("ERROR:/0");
    }
  }
  else
  {
    Serial.println("ERROR:/0");
  }
  return 0;
}