How do you convert a character into ASCII?

Answer 1

A character (of type char) doesn't actually require conversion unless you need to print the ASCII value rather than the character itself, or where the result of a numeric operation exceeds the range of a char.

For instance:

char a = 'a'; // ASCII 97

char b = 'b'; // ASCII 98

printf("a + b = %c\n", a + b);

printf("a + b = %d\n", (int) a + b);

printf("a + b = %d\n", (int) (a + b));

In the above example, the output will be something like:

a + b = Ã

a + b = 195

a + b = -61

In the first print statement, the result of a + b is either 195 or -61 depending on whether a (plain) char is signed or unsigned. Either way, the corresponding character is printed. In this case the character 'Ã' is printed (the character corresponding to ASCII code 195 in the ISO 8859-1 extended ASCII table).

In the second print statement, we explicitly cast the variable a to an int, thus the result is an int with the value 195.

In the final print statement, we explicitly cast the result of a + b to an int. If a (plain) char is signed, then the result is -61 (because 195 is beyond the range of a signed char), otherwise the result is 195 (which is in the range of a signed char).