Introduction of an integer in C

Question

Introduction of an integer

Ask the user to enter an integer. if the user enters an integer rather than introduce such as 14 + 12. The program should show a message saying invalid character and ask to enter another number.

Help me resolution

Vulpes · Answer

So you only want to check that the input is an integer and, if it isn't, keep going until it is. In C# that would be : using System; class Program { static void Main() { int number; while(true) { Console.Write("Enter an integer : "); if(!int.TryParse(Console.ReadLine(), out number)) { Console.WriteLine("Not a valid integer. Please try again"); } else { Console.WriteLine("OK, bye"); return; } } } } or, if you want it in C : #include #define MAX_TRIES 1000 int main() { char s[80]; int i, valid, count; count = 0; while(count { printf ("Enter an integer: "); fgets(s, 80, stdin); valid = 1; for(i = 0; i { if(!isdigit(s[i])) { valid = 0; break; } } if (valid) { printf ("OK, bye"); return 0; } else { printf("Not a valid integer. Please try again.
"); count++; } } }

Vitor Ferreira · Answer

to introduce any character other than a number , the program should display a message of error and re-order to enter another number until the user enters a number without character

Vulpes · Answer

I'm not sure that I understand the question but try this: using System; class Program { static void Main() { while(true) { Console.Write("Enter an integer addition : "); string reply = Console.ReadLine(); string[] items = reply.Split('+'); if (items.Length == 1) { Console.WriteLine("Invalid addition, please re-enter"); } else { int[] numbers = new int[items.Length]; for(int i = 0; i int sum = 0; foreach(int number in numbers) sum += number; Console.WriteLine("The result is {0}", sum); Console.ReadKey(); return; } } } }