using System;class Program{ static void Main() { var random = new Random(DateTime.Now.Millisecond); int n = 3; var f = new int[n, n]; int c; Console.WriteLine("f:"); for (var i = 0; i < n; i++) { for (var j = 0; j < n; j++) { f[i, j] = random.Next(0, 9); Console.Write(f[i, j] + " "); } Console.WriteLine(); } Console.WriteLine(); for(int i = 0; i < n; i++) { if (f[i,0] != f[i,i]){ c = f[i,0]; f[i,0] = f[i,i]; f[i,i] = c; } } Console.WriteLine("New f:"); for(int i = 0; i < n; i++){ for (var j = 0; j < n; j++) Console.Write(f[i,j] + " "); Console.WriteLine(); } Console.WriteLine(); Console.ReadKey(); }}Пример:f:
8 1 0 3 6 3 0 5 7 New f:
8 1 0 6 3 3 7 5 0