Is there any difference between 1U and 1 in c? -

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    while ((1u << i) < nsize) {         i++;     }

any particular reason use 1u instead of 1?

on compliers, both give result same representation. however, according c specification, result of bit shift operation on signed argument gives implementation-defined results, in theory 1u << i more portable 1 << i. in practice c compilers you'll ever encounter treat signed left shifts same unsigned left shifts.

the other reason if nsize unsigned, comparing against signed 1 << i generate compiler warning. changing 1 1u gets rid of warning message, , don't have worry happens if i 31 or 63.

the compiler warning reason why 1u appears in code. suggest compiling c warnings turned on, , eliminating warning messages changing code.


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