typecasting to unsigned in C

Question

int a = -534;
unsigned int b = (unsigned int)a;
printf("%d, %d", a, b);

prints -534, -534

Why is the typecast not taking place?

I expected it to be -534, 534

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If I modify the code to

int a = -534;
unsigned int b = (unsigned int)a;
if(a < b)
  printf("%d, %d", a, b);

its not printing anything... after all a is less than b??

Answer 1

Because you use %d for printing. Use %u for unsigned. Since printf is a vararg function, it cannot know the types of the parameters and must instead rely on the format specifiers. Because of this the type cast you do has no effect.