using System;

public static class Lab$4\_2$

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public static void Main$()$

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const int PASS $=50$;

int numPass$=0,$ numFail$=0,$ totalMarks$=0$;

double mark, perPass$=0,$ perFail$=0$;

$//$ loop to read in a valid mark or the sentinel value

do

$\{$

$//$ Read initial mark $($seed the loop$)$

Console.Write$("$Enter a mark between $0$ and $100(-$ve value to stop$)$: $")$;

mark $=$ Convert.ToDouble$($Console$.$ReadLine$())$;

$\}$ while $($mark $>100)$;

$//$ if the inputted mark is not the sentinel value, process it

while $($mark $>=0)$

$\{$

$//$ increment the counter for the total number of data values

$//***$ Insert code

$//$ Determine if the mark is a pass or fail $($If statement$)$

$//***$ Insert code

$//$ Read next mark

$//***$ Insert code

$\}$

$//$ Calculate the percentage of marks that were passes and fails

$//***$ Insert code

$//$ Print results

Console.WriteLine$("$Total number of marks $=\{0\}",$ totalMarks$)$;

Console.WriteLine$("$Percentage of passing marks $=\{0$:P$1\}",$ perPass$)$;

Console.WriteLine$("$Percentage of failing marks $=\{0$:P$1\}",$ perFail$)$;

Console.ReadLine$()$;

$\}$

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