added fifth task

Author: hackerSa3edy

0x02-functions_nested_loops/4-isalpha.c

@@ -0,0 +1,20 @@
+#include "main.h"
+
+/**
+ * _isalpha - Checks if the char is alpha.
+ *
+ * @c: The char to be checked.
+ *
+ * Return: return (1) if c is letter, (0) otherwise.
+ */
+int _isalpha(int c)
+{
+	if ((c >= 97 && c <= 122) || (c >= 65 && c <= 90))
+	{
+		return (1);
+	}
+	else
+	{
+		return (0);
+	}
+}

0x02-functions_nested_loops/main.h

@@ -2,3 +2,4 @@ int _putchar(char);
 void print_alphabet(void);
 void print_alphabet_x10(void);
 int _islower(int);
+int _isalpha(int);