Exercise 2 of 10 · Conditionals

Spelling Test Pass Checker

What you will make

A program that takes a student's spelling test score and prints whether they passed.

The one new idea: Branching with if/else based on a comparison

Programs constantly need to make decisions — pass or fail, eligible or not — and if/else is how code chooses between paths based on a condition.

Go straight to the code ↓

Programs often need to choose between two different responses depending on some condition — pass or fail, eligible or not. In C#, an if statement runs its block only when its condition (a bool expression) is true; an optional else block runs when that same condition is false. Conditions are built with comparison operators: == (equal), != (not equal), <, >, <=, >=. It's easy to mix up = (assignment) with == or another comparison operator — and in C#, that mistake usually shows up immediately as a compiler error, because if requires a bool, and assigning an int doesn't give you one. This kind of check comes up constantly, anywhere a program needs to decide between two outcomes based on a number it was handed.

Worked example

Here's a food truck order checked against a delivery minimum:

double orderTotal = 18.50;
double deliveryMinimum = 15.00;

Console.WriteLine($"Order total: {orderTotal}");

if (orderTotal >= deliveryMinimum)
{
    Console.WriteLine("Delivery: Eligible");
}
else
{
    Console.WriteLine("Delivery: Add more to qualify");
}

Output

Order total: 18.5
Delivery: Eligible

The condition orderTotal >= deliveryMinimum compares two numbers and produces a bool, which is exactly what if needs to decide which block to run.

Your turn

The starter code checks a spelling test score against a passing score. Its if condition uses a single = instead of a comparison operator, so it's trying to assign passingScore into score right inside the condition — which doesn't compile, because the result of an assignment isn't automatically a bool here. Fix the condition so it correctly checks whether score is greater than or equal to passingScore.

If something goes wrong

If you get a compiler error like "cannot implicitly convert type 'int' to 'bool'", that's the assignment-instead-of-comparison bug — look for a lone = inside an if (...) and change it to a real comparison operator. If the program compiles but prints the wrong result, check the direction of your comparison, since >= and <= are easy to flip by accident and both compile just fine.

Write your code

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Ready

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Things that often go wrong here

Writing = instead of == (or a proper comparison operator) inside a condition.: A single = assigns a value and, for non-bool types like int, won't even compile inside an if statement's parentheses.
Getting the comparison direction backwards, such as using <= when >= was intended.: This silently flips which cases count as passing, without any compiler error to catch it.
Assuming the else branch only runs for some specific 'opposite' case.: else always runs whenever the if condition is false — there's no in-between state to account for.

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