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help converting integers to strings and concatenating in C
I'm trying to convert two integers into strings, concatenate them, and convert the result back to an integer. I'm not sure the best way to do this. I tried using sprintf but it didn't work and the characters were null when I printed them out.
Here are the relevant parts of the code:
alt_u8 high_digit, low_digit;
char high_digit_char, low_digit_char, full_value_char;
sprintf(high_digit_char, "%d", high_digit);
sprintf(low_digit_char, "%d", low_digit);
sprintf(full_value_char, "%s %s",high_digit_char, low_digit_char);
full_value = atoi(full_value_char);
Here are the relevant parts of the code:
alt_u8 high_digit, low_digit;
char high_digit_char, low_digit_char, full_value_char;
sprintf(high_digit_char, "%d", high_digit);
sprintf(low_digit_char, "%d", low_digit);
sprintf(full_value_char, "%s %s",high_digit_char, low_digit_char);
full_value = atoi(full_value_char);
Programming Languages-OtherC
Last Comment
ozo
//or
char full_value_char[99];
sprintf(full_value_char, "%d%d",high_digit,low_digi
char full_value_char[99];
sprintf(full_value_char, "%d%d",high_digit,low_digi
if you use full_value_char[3],
"%1s%1s" should have been "%.1s%.1s"
"%1s%1s" should have been "%.1s%.1s"
ASKER
I'm still not getting the correct result, these are the integer and corresponding character values printed out:
high int: 18 low int: 18
full val int: 2c
low char: 4 high char: 4
full char: 44
What is the point of the %10 in high_digit%10 within the sprintf?
Maybe I should post another part of the code:
high_digit = bcd_convert(high_digit);
low_digit = bcd_convert(low_digit);
alt_u8 bcd_convert(alt_u8 val_convert)
{
switch(val_convert){
case 0:
val_convert = 0xC0;
break;
case 1:
val_convert = 0xF9;
break;
case 2:
val_convert = 0x24;
break;
case 3:
val_convert = 0x30;
break;
case 4:
val_convert = 0x19;
break;
case 5:
val_convert = 0x12;
break;
case 6:
val_convert = 0x03;
break;
case 7:
val_convert = 0xF8;
break;
case 8:
val_convert = 0x00;
break;
case 9:
val_convert = 0x18;
break;
}
return val_convert;
}
The high digit and low digit are converted to these hex values, so for example if high digit is 9 and low digit is 9, I would want "1818" to be the full value.
high int: 18 low int: 18
full val int: 2c
low char: 4 high char: 4
full char: 44
What is the point of the %10 in high_digit%10 within the sprintf?
Maybe I should post another part of the code:
high_digit = bcd_convert(high_digit);
low_digit = bcd_convert(low_digit);
alt_u8 bcd_convert(alt_u8 val_convert)
{
switch(val_convert){
case 0:
val_convert = 0xC0;
break;
case 1:
val_convert = 0xF9;
break;
case 2:
val_convert = 0x24;
break;
case 3:
val_convert = 0x30;
break;
case 4:
val_convert = 0x19;
break;
case 5:
val_convert = 0x12;
break;
case 6:
val_convert = 0x03;
break;
case 7:
val_convert = 0xF8;
break;
case 8:
val_convert = 0x00;
break;
case 9:
val_convert = 0x18;
break;
}
return val_convert;
}
The high digit and low digit are converted to these hex values, so for example if high digit is 9 and low digit is 9, I would want "1818" to be the full value.
fullvalue = bcd_convert(high_digit)<<8
printf("%04x\n",fullvalue)
printf("%04x\n",fullvalue)
ASKER
It's still not working, I added to the printf statement to print the high and low digits separately:
printf("high: %x low: %x full: %04x\n",high_digit,low_dig
and this is part of the result:
high: 18 low: 12 full: 0000
high: 18 low: 3 full: 0000
high: 18 low: f8 full: 0018
high: 18 low: 0 full: 1800
high: 18 low: 18 full: 0018
printf("high: %x low: %x full: %04x\n",high_digit,low_dig
and this is part of the result:
high: 18 low: 12 full: 0000
high: 18 low: 3 full: 0000
high: 18 low: f8 full: 0018
high: 18 low: 0 full: 1800
high: 18 low: 18 full: 0018
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ASKER
Thank you, there is just one slight problem:
When there is a single digit (0x00 or 0x03), this happens:
high: c0 low: 3 full: c030
high: f9 low: 0 full: f9c0
Do you know how to fix that? Thank you!!
When there is a single digit (0x00 or 0x03), this happens:
high: c0 low: 3 full: c030
high: f9 low: 0 full: f9c0
Do you know how to fix that? Thank you!!
bcd_convert(3)==30
bcd_convert(0)==0xc0
if you don't want that, don't bcd_convert
fullvalue = (high_digit<<8)+low_digit;
bcd_convert(0)==0xc0
if you don't want that, don't bcd_convert
fullvalue = (high_digit<<8)+low_digit;
ASKER
Thank you!
What is the point of the %10 in high_digit%10 within the sprintf?To ensure that %d only prints a single digit.
Your original code tried to put %d into a single character, so high_digit_char[2] allocated space for a single character string, with null terminator.
if %d was permitted to print more than a single digit, it would have overflowed the space available.
sprintf(high_digit_char, "%d", high_digit%10);
sprintf(low_digit_char, "%d", low_digit%10);
sprintf(full_value_char, "%1s%1s",high_digit_char, low_digit_char);
full_value = atoi(full_value_char);