added weekly exercises of isp-ws25

c/isp-ws25/weeklies/week02/w02ex03.c

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+/*
+[x] Get user input as char
+[x] check if valid input ([ A- Z][ a-  z])
+[x] check if valid input ([65-90][97-122])
+[x] if valid, print numerical
+[x] if valid, print ASCII
+[x] if invalid, print "[ERROR] not a valid character [A-Z] or [a-z]"
+[x] if invalid, no further output
+[x] request input repeatedly
+[x] print round number at start
+[x] if "Q" or "q", terminate
+[x] regular output when terminating
+[x] print "GOODBYE" before terminating
+*/
+
+unsigned char userchar = 0;
+unsigned int counter = 1;
+
+bool charcheck(unsigned char char_)
+{
+    if((char_ >= 65 && char_ <= 90) || (char_ >= 97 && char_ <= 122)) // A <= %c <= Z OR a <= %c <= z
+    {
+        return true;
+    }
+    else
+    {
+        return false;
+    }
+}
+
+void round_start()
+{
+    printf("Round %d:\n", counter);
+    counter++;
+    printf("%s", "Insert character: ");
+}
+
+int main()
+{
+    while(1)
+    {
+        round_start();
+        scanf(" %c", &userchar);
+        
+        if (charcheck(userchar) == true)
+        {
+            printf("%-17s %d\n", "Number:", userchar);
+            printf("%-17s %c\n", "ASCII character:", userchar);
+            //Q == 81, q == 113
+            if (userchar == 81 || userchar == 113) {break;}
+        }
+        else
+        {
+            printf("[ERROR] not a valid character [A-Z] or [a-z]\n");
+            continue;
+        }
+    }
+
+    printf("GOODBYE\n");
+    return 0;
+}