add help text

1 files changed, 7 insertions, 4 deletions

diff --git a/yacas.c b/yacas.c
index dc44f22..e1bbe77 100644
--- a/yacas.c
+++ b/yacas.c
@@ -1493,7 +1493,7 @@ int main(int argc, char *argv[])
 
     if(interactive)
     {
-        printf("Welcome to yaCAS\n\nCopyright (C) 2018 Franklin Wei\n\nType \"help\" for a quick overview of the supported features.\n\n");
+        printf("Welcome to yaCAS!\n\nCopyright (C) 2018 Franklin Wei\n\nType \"help\" for a quick overview of the supported features.\n\n");
     }
 
     atexit(freevars);
@@ -1541,10 +1541,13 @@ int main(int argc, char *argv[])
             else if(!strcmp(line, "help"))
             {
                 printf("yaCAS requires a space between all tokens, so instead of \"x^2\", type \"x ^ 2\"\n");
+                printf("Some features in action:\n");
 
-                printf("Calculation: try \"atan ( 1 ) / pi\"\n");
-                printf("Differentiation: try \"x ^ 2 diff x\", \"log ( y ) * x diff x\"\n");
-                printf("Special functions: try \"exp ( pi ) - pi\"\n");
+                printf("Calculation:\n    > atan ( 1 ) / pi\n");
+                printf("Differentiation:\n    > x ^ 2 diff ( x = 2 ) -- differentiate x^2 at x=2\n    > log ( y ) * x diff x -- implicit differentiation\n    > exp ( x ^ 2 ) diff x diff ( x = 0 ) -- evaluate higher-order derivative\n");
+                printf("Special functions:\n    > exp ( pi ) - pi\n");
+                printf("Variables:\n    > y = x ^ 2 -- variables can contain other expressions\n    > y diff x -- differentiate x^2 with respect to x\n    > x = 2\n    > y\n");
+                printf("Equality testing (rudimentary):\n    > x + 2 == 2 + x\n");
                 free(line);
                 continue;
             }