C Brain Teasers: Exercise Your Mind/

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Discussion: On the Case

Discussion: On the Case

Execute code to understand the output and gain insights into bitwise operators ( | , & ).

We'll cover the following...

Run the code

Now, it's time to execute the code and observe the output.

C
#include <stdio.h>
int main()
{
  char a;
  for( a='A'; a<='Z'; a++ )
    putchar( a | 0x20 );
    putchar('\n');
  for( a='a'; a<='z'; a++ )
    putchar( a & 0xdf );
    putchar('\n');
    
return(0);
}

Understanding the output

Two lines are output:

abcdefghijklmnopqrstuvwxyz
ABCDEFGHIJKLMNOPQRSTUVWXYZ
Code output

The uppercase letters are converted into lowercase. Lowercase letters are converted to uppercase.

Explanation

Most C programmers rush to the ctype functions when letters need case conversions. The toupper() and tolower() ...