Memfault State of IoT Report

(So far, 49 people got it right out of 423 for a success rate of 11%)

(Thank you to Jason Sachs for submitting this question)

What does kapow() return in this C program?

#include <stdint.h>
uint32_t howjadoo(uint32_t prevsum, uint16_t command, uint16_t response)
    return prevsum + (command - response);
uint32_t kapow()
    return howjadoo(100000, 10001, 10002);
Pick one:
it depends on sizeof(int)
this is implementation-defined behavior
this is undefined behavior

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Comment by QLNovember 2, 2022

Interesting quiz! One quick correction to the explanation section, which says "On machines where an int is 8 or 16 bits,...". The int type in C cannot be only 8-bit wide even on 8-bit CPU. This is because the C Standard says that "Basic signed integer type. Capable of containing at least the [−32,767, +32,767] range."

[ - ]
Comment by jms_nhNovember 2, 2022
ah -- thanks, I missed that detail!
[ - ]
Comment by rbonvinoNovember 7, 2022

Good point I didn't know about

[ - ]
Comment by TurbonattaNovember 2, 2022

Well, I could understand the result if the quiz was written using "int", "unsigned int", "long" and "unsigned long" which are processor dipendent but every I looked it says that uint16_t is 2 bytes and uint32_t is 4 bytes regardless the processor. I am confused.

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