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/*
* Shows how the conversion between signed and unsigned are made.
* Most machines follow the rule that the underlying bit pattern doesn't change.
* Let's see
*/
#include <stdio.h>
/* 10101010
* integers are usually considered signed by default unless we append
* the suffix U to the number*/
#define NUM 0xAA
int x = -1;
unsigned u = 2147483648;
int main(void) {
unsigned char a = NUM;
printf("Original unsigned number - HEX: 0x%.2X %d\n", a, a);
/* there is no formatter to print a single byte integer, printing it
* with %d would result in a cast to integer, printing 4 bytes, so let's
* print it only in HEX
*/
printf("Signed conversion number - HEX: 0x%.2X DEC: %d\n", (char)a, (signed char)a);
printf("x = %d - x = %u - 0x%X\n", x, x, x);
printf("u = %d - u = %u - 0x%X\n", u, u, u);
/*
* When one of the operands in an equation is unsigned, C will cast the
* another operand to unsigned too before making the operation
*/
printf("%X\n", -2147483647);
return 0;
}
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