Joined: Sun Oct 03 2010, 01:40AM Location (Home Town): Tibanga ILigan city Philippines Posts: 1072
sure ajay. But its very difficult to make a progress hehe. i have a based code but it is in tcl language my big problem is converting it to python. Wtf! Hehe
i cant get a help here since you don know tcl and python.
Joined: Sun Oct 03 2010, 01:40AM Location (Home Town): Tibanga ILigan city Philippines Posts: 1072
actually Im using that code above. I modified it and its working fine... i just used that without understanding and now i need someone to explain that to me.... hehehe eheheh thanks in advance..... heheh
Joined: Fri Feb 24 2006, 07:56AM Location (Home Town): Punjab, India Posts: 12590
thats how structures in C/C++ are used. it looks like you never used structure. here is a quick reference
Defining structure
CODE:
//defining structure struct mystruct { int a; char b; char c[10]; int d[10]; };
Now mystruct is name of structure. a,b,c and d are members of structure. its like grouping set of variables in a single datatype and giving your own name to it.
to use a structure, you first need to create an instance of the structure. and members of structure can only be accessed through that instance.
CODE:
//defining instance of struct struct mystruct x,y,*z;
so x and y are two instances of structure. and z is a pointer to mystruct.
using structure is very simple, lets say you want to equate members of structure x with y then you will do like this.
CODE:
x.a= y.a;
x.b= y.b;
memcpy(x.c, y.c,10);//copy character array
Pointers work a little different way we use dot (.) incase of structure variables to access the members but incase of pointers we use arrows (->) e.g.
CODE:
z =&x;//z has address of x, or say z points to x now.
y.a= z->a;//you see the difference now?
y.b= z->b; //its same with all.. just replace . with ->
Initializing structure: structures are initialized just like we do in arrays. each member is separated by comma and complete thing is enclosed in curly brackets.
CODE:
x ={10,'c',"hello",{10,20,30,40,50,60,70,80,90,100}};
//partially defining structure
y ={30,'y',"world"}; //now the integer array will automatically be initialized to 0.
Working example: lets take an example, I want to make database of user accounts in C. I can have total of 100 users. user info will have username, password, age etc. so if you just do it in traditional style what you will do is.. you will create three arrays to store information of each user.
CODE:
//array style.. char username[100][20];//100 usernames each of length 20 max char password[100][15];//100 passwords each of length 15 max int age[100];//array to store age of 100 users
now if you write code using the above style you will have to manage lot of arrays which might get your code look very complex. So now lets see structure style for the same..
CODE:
struct users { char username[20]; char password[15]; int age; };
that defines a custom data type with name users. now lets create 100 users.
CODE:
struct users user[100]; //we define array of 100 1 structure for each user.
lets make simple login checker now.. a function that checks if entered user details are correct or not.
CODE:
int checkuser(struct users input){ int i; int status =0; //we have 100 users so loop will go from 0 to 99 //checking each user.. for(i=0; i<100; i++){ if(strcmp(input.username, user[i].username)==0){//check if username is there in database or not if(strcmp(input.password, user[i].password)==0){//check if password matches
status =1;//set status to 1 so that we say input user is available in database break;//break out of loop, we are done with checking }else{
status =-1;//username is there but password incorrect break;//break out of loop. } } } if(i ==100){ //if i reaches 100 it means username not available in database
status =-2; } return status;//return status to caller function }
well i think small tutorial on structures is good enough hope you now learn how to use structures, how to pass structure as a varaible to function, defining a structure pointer and variable etc.
Joined: Sun Oct 03 2010, 01:40AM Location (Home Town): Tibanga ILigan city Philippines Posts: 1072
guys i need help again... How do i call the function mx_cal(); ?? what is that u8 line parameter? i dont have idea how do i call that from the function i made below which is burned_cal();
// Convert global variables to local variables //kcalories = mel.calories/1000;
met = mel.met_value/1000; if(sys.flag.use_metric_units) weight = mel.user_weight; else weight =((s32)mel.user_weight*2205)/1000;// Convert kg to lb
// Init value index
select =0;
// Loop values until all are set or user breaks set while(1) { // Idle timeout : exit without saving if(sys.flag.idle_timeout)break;
// Button STAR (short): save, then exit if(button.flag.star) { // Store local variables in global structure //mel.calories = kcalories*1000; //mel.user_sex = sex;
mel.met_value= met*1000; if(sys.flag.use_metric_units) mel.user_weight= weight; else mel.user_weight=(weight *1000)/2205;
// Set display update flag
display.flag.line1_full_update=1;
break; }
switch(select) {
case0:// Set user weight
clear_line(LINE2); if(sys.flag.use_metric_units) {
display_chars(LCD_SEG_L2_1_0,(u8 *)"KG", SEG_ON);
set_value(&weight,3,2, USER_WEIGHT_MIN_KG, USER_WEIGHT_MAX_KG, SETVALUE_DISPLAY_VALUE + SETVALUE_NEXT_VALUE, LCD_SEG_L2_4_2, display_value1);
hallo mr.ajay.... can u please post the assembly code for displaying anything on the lcd in 4 bit mode.... i'm working with pic 16f913.... i just getting blocks in the led...i know it is the problem with the initialisation...how to initialise the lcd in 4 bit mode...
Anonymous | 20 May : 07:05
hai............
Anonymous | 17 May : 22:28
anyone can pls tell me how to program for moving message on 16*2 lcd by using 8051C in keil
hope you now learn how to use structures, how to pass structure as a varaible to function, defining a structure pointer and variable etc. 
