What happens when I use the wrong format specifier?
Solution 1:
what happens when I use the wrong format specifier in C?
Generally speaking, undefined behaviour.*
However, recall that printf is a variadic function, and that the arguments to variadic functions undergo the default argument promotions. So for instance, a char is promoted to an int. So in practice, these will both give the same results:
char x = 'A';
printf("%c\n", x);
int y = 'A';
printf("%c\n", y);
whereas this is undefined behaviour:
long z = 'A';
printf("%c\n", z);
* See for example section 7.19.6.1 p9 of the C99 standard:
If any argument is not the correct type for the corresponding conversion specification, the behavior is undefined.