Practice questions on Decide if/else

#include <iostream>
int main()
{
    using namespace std;

    int length,breadth;
    cout<<"Enter length"<<endl;
    cin>>length;
    cout<<"Enter breadth"<<endl;
    cin>>breadth;

    if(length==breadth)
    {
        cout<<"It is a square"<<endl;
    }
    else
    {
        cout<<"It is a rectangle"<<endl;
    }

    return 0;
}									

#include <iostream>
int main()
{
	using namespace std;
	int quantity,price;
	cout << "Enter quantity" << endl;
	cin >> quantity;
	price = quantity*100;
	if (price>1000){
		cout << "Total cost is " << price-(price*.1) << endl;
	}
	else{
		cout << "Total cost is " << price << endl;
	}
	return 0;
}									

#include <iostream>
int main()
{
	using namespace std;
	int marks;
	cout << "Enter marks" << endl;
	cin >> marks;
	
	if (marks < 25){
		cout << "F" << endl;
	}
	else if(marks >=25 && marks <45){
		cout << "E" << endl;
	}
	else if(marks >=45 && marks <50){
		cout << "D" << endl;
	}
	else if(marks >=50 && marks <60){
		cout << "C" << endl;
	}
	else if(marks >=60 && marks <80){
		cout << "B" << endl;
	}
	else if(marks >=80 && marks <100){
		cout << "A" << endl;
	}
	else{
		cout << "Invalid marks" << endl;
	}
	return 0;
}									

#include <iostream>
int main()
{
    using namespace std;

    int x;
    cout<<"Enter a number"<<endl;
    cin>>x;
    if(x<0)
    {
        x = x*(-1);
    }

    cout<<"Absolute value is "<<x<<endl;


    return 0;
}