Question

I am having trouble with unsigned char *. Here is my code:

unsigned char *str=NULL;
str= (unsigned char*) realloc(str, 10*sizeof(unsigned char));
int number=10;
str[0]=(unsigned char) number;

Whenever I try to see str[0] with cout, it shows something else other than 10. I also have trouble when putting other variable into str:

unsigned char c='c';
str[0]=c;
cout<<str[0];

str[0] would output a. What am I missing?

Answer 1

s[0] = 10; means put character code 10 into the first location of array s. Try:

s[0] = '1'; s[1] = '0'; s[2] = '\0';

Probably you would like instead to use the function itoa(10, s, 10);

See itoa manual, the function itoa is declared as…

char* itoa(int valueToConvert, char* outputBuffer, int base);

If you try to do cout << character; it will print the character, not the character code. To print the character code you should do cout << (int)character;. Don’t use unsigned char for characters, characters are, well, signed chars, simply chars, for friends.