Just a diff...

diff.diff

--- test-old.cc	2019-01-30 22:49:33.481304795 -0700
+++ test.cc	2019-01-30 23:39:32.564553393 -0700
@@ -69,13 +69,13 @@
 
 int main()
 {
-    const int maxLength = 100;
+    const int maxLength = 101;
     char inputChar = '\0';
 
     do
     {
         printf("Type a string of text:\n");
-        char *buffer = calloc(maxLength, sizeof(char));
+        char *buffer = (char*) calloc(maxLength, sizeof(char));
 
         fgets(buffer, maxLength, stdin);
         printf("\n");
@@ -96,14 +96,15 @@
         printStringAsTriangle(buffer);
         printf("\n");
 
-        printf("Length of string: %i\n", strlen(buffer));
+        printf("Length of string: %li\n", strlen(buffer)-1);
 
         printf("Type another string? (y/n)\n");
         
-        inputChar = getchar();
+        scanf(" %c", &inputChar);
         clearInputBuffer();
+        free(buffer);
 
     } while (inputChar == 'y');
 
-    return 1;
+    return 0;
 }