I have written a routine to update an array using sprintf statement but after the execution the array doesnt seem to update. I am clueless where i have made the mistake. Can anybody help me? The program is given below.
#include<reg669.h> #include<stdio.h>
xdata unsigned char *Arr[3]; xdata unsigned int Val = 1; xdata unsigned int Val1 = 2;
void main(void) { S0CON = 0x50; //SERIAL COM IN MODE 1 TMOD = 0x20; //TIMER 1 IN AUTO RELOAD MODE TH1 = 0xFD; //BAUD RATE IS 19200 TL1 = 0x00; TR1 = 1; //ENABLE TIMER 1 Arr[0] = "LCD Testing "; Arr[1] = "Programming of LCD"; sprintf(Arr[1],"%s%u",Arr[1],Val); Arr[2] = "Sprintf testing "; sprintf(Arr[2],"%s%u",Arr[2],Val1); SBUF=' '; printf(Arr[0]); TI_0 = 0; Delay(1000); SBUF=' '; printf(Arr[1]); TI_0 = 0; Delay(1000); SBUF=' '; printf(Arr[2]); TI_0 = 0; Delay(1000); while(1); }
The 1st printf works fine whereas for the 2nd and 3rd printf statments the integer value doesnt come alont with string. I dont know the reason....
I am clueless regarding the mistake i have done.
xdata unsigned char *Arr[3][20]; xdata unsigned int Val = 1; xdata unsigned int Val1 = 2;
void main(void) { S0CON = 0x50; //SERIAL COM IN MODE 1 TMOD = 0x20; //TIMER 1 IN AUTO RELOAD MODE TH1 = 0xFD; //BAUD RATE IS 19200 TL1 = 0x00; TR1 = 1; //ENABLE TIMER 1 Arr[0][20] = "LCD Testing "; Arr[1][15] = "Programming of LCD"; sprintf(Arr[1][20],"%s%u",Arr[1][15],Val); Arr[2][15] = "Sprintf testing "; sprintf(Arr[2][20],"%s%u",Arr[2][15],Val1); SBUF=' '; printf(Arr[0][20]); TI_0 = 0; Delay(1000); SBUF=' '; printf(Arr[1][20]); TI_0 = 0; Delay(1000); SBUF=' '; printf(Arr[2][20]); TI_0 = 0; Delay(1000); while(1); }
Andy as u said i have changed the 1D array to 2D array but according the above the result was,
LCD Testing Sprtinf testing 2 Sprintf testing 2
If i disable the sprintf statement and print the ouput for Arr[2][20] then the output is,
LCD Testing Programming of LCD 1 Programming of LCD 1
Even though i disabled sprtinf statement for Arr[2][20].
Wrong! You have added an extra dimension to your array, but are still playing with pointers, instead of characters. Away with the star in the declaration.
Your code:
Arr[1][15] = "Programming of LCD"; sprintf(Arr[1][20],"%s%u",Arr[1][15],Val);
Will manage the first assign, but the line will not mean what you think it means.
The second line - sprintf() will still not print to a text buffer, but will get an unassigned pointer to use for buffer. And even if Arr would have been correctly initialized with 15*20 pointers, the individual indices are 0..14 and 0..19, and you are making use of the index 20, i.e. the 21th entry of a dimension that has only 20 entries...
But for the optimum, replace Val with an array of 15 entries, and build the string whenever the users presses the up or down button. Then you don't need the sprintf() at all.
... and think more carefully about pointers, arrays, strings, etc
xdata unsigned char *Arr[3][20];
Should be:
xdata unsigned char Arr[3][20];
ie, an array of three 20-character strings (and don't forget that the 20 includes the NUL terminator - so that's only 19 usable characters)
Arr[0][20] = "LCD Testing ";
No, you can't do that!
You need to copy that text into the string
Again, you can't do that!
you need something like:
sprintf( Arr[1], "Programming of LCD %u", Val );
and you will need to repeat that each time you want to display a new value of 'Val'...
I still don't think this array of strings is helping you - you are still going to have to rebuild each string immediately before you display it - so you might just as well use printf directly!
Can't you just use something like:
void display_a_value( unsigned char value_id ) { switch( value_id ) { case 0: printf( "this value is: %u" this_value ); break; case 1: printf( "that value is: %u" that_value ); break; case 2: printf( "the other value is: %u" the_other_value ); break; etc... } }
Of course, you'd need some meaningful identifiers, and there's room for some optimisation - but that's the basic idea.
Always start with the basics; optimise later!