printing numbers question

[wolfv]

Why is the following code example not print the number eight?

#include <iostream>
#include <inttypes.h>

int main()
{
	uint8_t num8 = 8;

	std::cout << "start>>" << num8 << "<<the_end" << std::endl;
}

output:

start><<the_end

expected output:

start>>8<<the_end

Thank you.

[wildblue]

Works using printf.

http://www.cplusplus.com/reference/cinttypes/

1 2 3 4 5 6 7 8 9 10 11

#include <cstdio> #include <inttypes.h> int main() { uint8_t num8 = 8; printf("start >> %u << the_end", num8); return 0;

start >> 8 << the_end

[keskiverto]

There is no ostream<< for uint8_t. Therefore, the compiler picks some of the existing overloads. Perhaps char.

Easy to test. What does uint8_t num8 = 'r'; print with stream?


Explicit casting of num8 to (larger) numeric type would guide the selection of the <<.

[wolfv]

Thank you keskiverto, explicit casting worked.

#include <iostream>
#include <inttypes.h>

int main()
{
	uint8_t num8 = 8;

	std::cout << "start>>" << (int)num8 << "<<end" << std::endl;
}