## Solutions

### 5. if and for Statements

#### Exercise 1:

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

int main()
{
for(double i=1; i<=20; i++)
cout << "The square of " << i << " is " << i*i << endl;
}
```

#### Exercise 2:

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

int main()
{
double n=0;
cin >> n;

for(double i=1; i<=n; i++)
cout << "The square of " << i << " is " << i*i << endl;
}
```

#### Exercise 3:

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

int main()
{
double a=0;
cin >> a;
double b=0;
cin >> b;

if (a<b)
cout << "The smaller number is " << a << endl;
else
cout << "The smaller number is " << b << endl;
}
```

#### Exercise 4:

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

int main()
{
double num1=0;
double num2=0;
double num3=0;
cout << "Type in three different numbers: " << endl;
cin >> num1;
cin >> num2;
cin >> num3;

if (num1<num2 && num1<num3)
cout << "The smallest one is " << num1 << endl;
if (num2<num1 && num2<num3)
cout << "The smallest one is " << num2 << endl;
if (num3<num1 && num3<num2)
cout << "The smallest one is " << num3 << endl;
}
```

Note: A much better solution of this problem can be written by using functions.

#### Exercise 5:

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

int main()
{
cout << "Type in a natural number: " << endl;
double n=0;
cin >> n;

if (n>=10 && n<100)
cout << "The given number has exactly two digits." << endl;
else
cout << "The given number doesn't have exactly two digits."
<< endl;
}
```

#### Exercise 6:

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

int main()
{
cout << "Type in the annual income of a company:" << endl;
double income=0;
cin >> income;
cout << "Type in the annual expenses of a company:" << endl;
double expenses=0;
cin >> expenses;

double tax=0;
if (income > expenses)
tax = (income - expenses)*0.2;
cout << "Profit tax: " << tax << endl;
}
```