Realize the size of the letter C language conversion

#include <stdio.h>
/**
    The main use is the conversion between ASCII and ASCII character value to achieve this function
*/
int main(void)
{
    char n-= ' A ' ;
     // the printf ( "% D \ n-", n-); explain, char is an integer type, only one byte, the value of the output here is equivalent to complete conversion of a value type, ASCII output code is the value of

    // random input letter case of 
    printf ( " Please enter whatever you want to convert a value: " );
    scanf ( " % c " , & the n-);
     // printf ( "% d \ the n-", the n-); test; Note that I output is% d,% c is not

    if (n <= 'z' && n >='a')
    {
        n- = n-- 32 ;     // finally explained in detail herein 
    } the else  IF (n-<= ' the Z ' && n-> = ' A ' )
    {
        n = n + 32;
    }

    // output n- 
    the printf ( "converted value: % C \ n- " , n-);

    return 0;
}

/**
    % C means to convert the integers to ASCII characters
*/