To evaluate the expression \( c + d - f \) for \( c = 7.7 \), \( d = 16 \), and \( f = 1 \), we can substitute the values in:
\[ c + d - f = 7.7 + 16 - 1 \]
Now, perform the addition and subtraction:
\[ 7.7 + 16 = 23.7 \] \[ 23.7 - 1 = 22.7 \]
Thus, the value of the expression is
\[ \boxed{22.7} \]