如果`char`转换为`int`，为什么``％c'`存在于`printf`中？

Question

In C you have the "%c" and "%f" formats flags for printf - and scanf -like functions. Both of these function use variable length arguments ... , which always convert floats to doubles and chars to ints .

My question is, if this conversion occurs, why do separate flags for char and float exist? Why not just use the same flags as for int and double ?

Related question:
Why does scanf() need "%lf" for doubles, when printf() is okay with just "%f"?

Answer 1

Because the way it gets printed out is different.

printf("%d \n",100); //prints 100
printf("%c \n",100); //prints d - the ascii character represented by 100

Answer 2

Because float and double have different machine representations or sizes, and calling conventions: many processors have registers dedicated to floating point which might be used for argument passing.

And the C standard requires that short arguments are converted to int and float arguments are converted to double .