A random number generator will always output $7$. Sam uses this random number generator once. What is the expected value of the output?
1. The expected value \( E(X) \) of a random variable \( X \) is defined as the sum of all possible values of \( X \) each multiplied by their respective probabilities. Mathematically, this is given by:
   \[
   E(X) = \sum_{i} x_i \cdot P(X = x_i)
   \]
   where \( x_i \) are the possible values of \( X \) and \( P(X = x_i) \) is the probability that \( X \) takes the value \( x_i \).

2. In this problem, the random number generator always outputs the number \( 7 \). This means that the only possible value of \( X \) is \( 7 \), and the probability of \( X \) being \( 7 \) is \( 1 \) (or \( 100\% \)).

3. Substituting these values into the formula for the expected value, we get:
   \[
   E(X) = 7 \cdot P(X = 7) = 7 \cdot 1 = 7
   \]

4. Therefore, the expected value of the output of the random number generator is \( 7 \).

The final answer is \(\boxed{7}\).