Strange behaviour of the pow function

by

You have set a to be an int. pow() generates a floating point number, that in SOME cases may be just a hair less than 100 or 10000 (as we see here.)

Then you stuff that into the integer, which TRUNCATES to an integer. So you lose that fractional part. Oops. If you really needed an integer result, round may be a better way to do that operation.

Be careful even there, as for large enough powers, the error may actually be large enough to still cause a failure, giving you something you don’t expect. Remember that floating point numbers only carry so much precision.

More Related Contents:

  1. return value of pow() gets rounded down if assigned to an integer
  2. pow() seems to be out by one here
  3. Does pow() work for int data type in C? [duplicate]
  4. pow() cast to integer, unexpected result
  5. Comparing two memory addresses and showing them equal
  6. How to print Number Like following format in c? [closed]
  7. How to generate numbers upto 18 digits, sum of whose reciprocals is a whole number [closed]
  8. Access of register STM32 CAN communication
  9. What is the use extra curly brackets in the code? What does it do?
  10. The most efficient way to implement an integer based power function pow(int, int)
  11. What is the difference between char * const and const char *?
  12. How do you determine the size of a file in C?
  13. How to make child process die after parent exits?
  14. Avoid trailing zeroes in printf()
  15. Why bit endianness is an issue in bitfields?
  16. Building a logarithm function in C without using float type
  17. X,Y passing size for the array in C function
  18. read comma-separated input with `scanf()`
  19. How to include needed C library using gcc?
  20. Use of #pragma in C
  21. Does reading from stdin flush stdout?
  22. C circular dependency
  23. Why the address of variable of child process and parent process is same
  24. Do forked child processes use the same semaphore?
  25. getchar does not stop when using scanf
  26. Check glibc version for a particular gcc compiler
  27. Trouble with float on C [duplicate]
  28. What does a “CALLBACK” declaration in C do?
  29. Comma operator in condition of loop in C
  30. How do I access local C variable in arm inline assembly?

Leave a Comment