C# Programming – Answers with Short Programs

Each question below includes a compact C# console-style solution snippet.

1. "42"

int n = int.Parse("42");
Console.WriteLine(n);

2. "12.34"

double d = double.Parse("12.34");
Console.WriteLine(d);

3. "1 2 3 4"

var nums = "1 2 3 4".Split(' ').Select(int.Parse);
Console.WriteLine(string.Join(",", nums));

4. "9.5 8.3 7.1"

var vals = "9.5 8.3 7.1".Split(' ').Select(double.Parse);
Console.WriteLine(vals.Average());

5. "Fifty"

bool ok = int.TryParse("Fifty", out _);
Console.WriteLine(ok ? "Valid" : "Invalid");

6. "15.7abc"

string s = "15.7abc";
double num = double.Parse(
    new string(s.TakeWhile(c => char.IsDigit(c) || c=='.').ToArray()));
Console.WriteLine(num);

7. "999999999"

long l = long.Parse("999999999");
Console.WriteLine(l);

8. "0xFF"

int x = Convert.ToInt32("FF", 16);
Console.WriteLine(x);

9. "3E+3"

double sci = double.Parse("3E+3",
    System.Globalization.CultureInfo.InvariantCulture);
Console.WriteLine(sci);

10. "42.5 36.1 -12"

var nums = "42.5 36.1 -12".Split(' ')
    .Select(double.Parse);
Console.WriteLine(nums.Sum());

11. " 75 "

int v = int.Parse("   75   ".Trim());
Console.WriteLine(v);

12. "3.14.15"

bool ok = double.TryParse("3.14.15", out _);
Console.WriteLine(ok ? "Valid" : "Invalid");

13. "1.000.000"

string s = "1.000.000".Replace(".", "");
int n = int.Parse(s);
Console.WriteLine(n);

14. "1,234.56"

double d = double.Parse("1,234.56",
 System.Globalization.NumberStyles.Any,
 System.Globalization.CultureInfo.InvariantCulture);
Console.WriteLine(d);

15. "(123)"

string s="(123)";
int n = -int.Parse(s.Trim('(',')'));
Console.WriteLine(n);

16. "12:30"

var p="12:30".Split(':');
int mins=int.Parse(p[0])*60+int.Parse(p[1]);
Console.WriteLine(mins);

17. "$1,500.75"

string s="$1,500.75".Replace("$","").Replace(",","");
double d=double.Parse(s);
Console.WriteLine(d);

18. "8 16 32 bits"

var sum = System.Text.RegularExpressions.Regex
 .Matches("8 16 32 bits", @"\d+")
 .Select(m=>int.Parse(m.Value)).Sum();
Console.WriteLine(sum);

19. "0b1011"

string s="1011";
int n=Convert.ToInt32(s,2);
Console.WriteLine(n);

20. "2,000 apples and 3,500 oranges"

var nums = System.Text.RegularExpressions.Regex
 .Matches("2,000 apples and 3,500 oranges", @"[\d,]+")
 .Select(m=>int.Parse(m.Value.Replace(",","")));
Console.WriteLine(nums.Sum());