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  1. #include <iostream>
  2. #include <inttypes.h>
  3.  
  4. uint64_t test_overflow(uint64_t start, uint64_t add, uint64_t check)
  5. {
  6. 	uint64_t count = 0;
  7. 	uint64_t sum1 = start;
  8. 	uint64_t sum2 = start;
  9. 	do
  10. 	{
  11.     	sum2 += sum1 += add;
  12.     	count++;
  13.     } while(sum1 < check && sum2 < check);
  14.     return count;
  15. }
  16.  
  17. int main() {
  18. 	std::cout << "Overflow of uint16_t after: " << test_overflow(0, UINT8_MAX, UINT16_MAX - UINT8_MAX) << " rounds (start value 0)." << std::endl;
  19. 	std::cout << "Overflow of uint32_t after: " << test_overflow(0, UINT16_MAX, UINT32_MAX - UINT16_MAX) << " rounds (start value 0)." << std::endl;
  20. 	std::cout << "Overflow of uint64_t after: " << test_overflow(0, UINT32_MAX, UINT64_MAX - UINT32_MAX) << " rounds (start value 0)." << std::endl;
  21. 	return 0;
  22. }
Success #stdin #stdout 0.35s 15240KB
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stdin
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Standard input is empty
stdout
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Overflow of uint16_t after: 23 rounds (start value 0).
Overflow of uint32_t after: 362 rounds (start value 0).
Overflow of uint64_t after: 683442533 rounds (start value 0).
https://ideone.com/7dHDCg
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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