C# program to check if all the values in a list that are greater than a given value

To check if all values in a list are greater than a given value, you need to iterate through each element and compare it against the threshold. If any element fails the condition, then not all values meet the criteria.

There are multiple approaches to solve this problem in C# − using traditional loops, LINQ methods, or built-in array methods.

Using Traditional For Loop

The most straightforward approach uses a for loop to iterate through the array and check each element −

using System;

public class Program {
    public static void Main(string[] args) {
        int[] arr = new int[] {55, 100, 87, 45};
        int threshold = 80;
        bool allGreater = true;
        
        Console.WriteLine("Array: [55, 100, 87, 45]");
        Console.WriteLine("Threshold: " + threshold);
        
        for (int i = 0; i < arr.Length; i++) {
            if (arr[i] <= threshold) {
                allGreater = false;
                break;
            }
        }
        
        Console.WriteLine("All values greater than " + threshold + ": " + allGreater);
        
        // Show which values are greater
        Console.WriteLine("Values greater than " + threshold + ":");
        for (int i = 0; i < arr.Length; i++) {
            if (arr[i] > threshold) {
                Console.WriteLine(arr[i]);
            }
        }
    }
}

The output of the above code is −

Array: [55, 100, 87, 45]
Threshold: 80
All values greater than 80: False
Values greater than 80:
100
87

Using LINQ All() Method

LINQ provides the All() method that returns true if all elements satisfy a given condition −

using System;
using System.Linq;

public class Program {
    public static void Main(string[] args) {
        int[] arr = new int[] {85, 100, 87, 95};
        int threshold = 80;
        
        Console.WriteLine("Array: [85, 100, 87, 95]");
        Console.WriteLine("Threshold: " + threshold);
        
        bool allGreater = arr.All(x => x > threshold);
        Console.WriteLine("All values greater than " + threshold + ": " + allGreater);
        
        // Count of elements greater than threshold
        int count = arr.Count(x => x > threshold);
        Console.WriteLine("Count of values greater than " + threshold + ": " + count);
    }
}

The output of the above code is −

Array: [85, 100, 87, 95]
Threshold: 80
All values greater than 80: True
Count of values greater than 80: 4

Using Custom Method with Early Exit

A reusable method that checks the condition and exits early when a false condition is found −

using System;

public class Program {
    public static bool AreAllGreater(int[] array, int threshold) {
        foreach (int value in array) {
            if (value <= threshold) {
                return false;
            }
        }
        return true;
    }
    
    public static void Main(string[] args) {
        int[] arr1 = new int[] {55, 100, 87, 45};
        int[] arr2 = new int[] {85, 100, 87, 95};
        int threshold = 80;
        
        Console.WriteLine("Testing array 1: [55, 100, 87, 45]");
        Console.WriteLine("All greater than " + threshold + ": " + AreAllGreater(arr1, threshold));
        
        Console.WriteLine("\nTesting array 2: [85, 100, 87, 95]");
        Console.WriteLine("All greater than " + threshold + ": " + AreAllGreater(arr2, threshold));
    }
}

The output of the above code is −

Testing array 1: [55, 100, 87, 45]
All greater than 80: False

Testing array 2: [85, 100, 87, 95]
All greater than 80: True

Comparison of Approaches

Conclusion

Checking if all values in an array are greater than a threshold can be accomplished using traditional loops, LINQ methods, or custom functions. The LINQ All() method provides the most concise solution, while traditional loops offer more control and no additional dependencies.