integer-overflow

来源： https://stackoverflow.com/questions/30606365/overflow-occurs-with-multiplication

来源： https://stackoverflow.com/questions/30606365/overflow-occurs-with-multiplication

来源： https://stackoverflow.com/questions/30606365/overflow-occurs-with-multiplication

问题 This question already has answers here : C++ literal integer type (2 answers) Closed 12 days ago . Why doesn't this code print same number? : long long a, b; a = 2147483647 + 1; b = 2147483648; printf("%lld\n", a); printf("%lld\n", b); I know that int variable's maximum number is 2147483647 because int variable is 4 byte. But as I know, long long variable is 8 byte, but why does that code act like that? 回答1: 2147483647 + 1 is executed as the sum of two ints and therefore overflows. 2147483648

问题 I use the pd.pivot_table() method to create a user-item matrix by pivoting the user-item activity data. However, the dataframe is so large that I got complain like this: Unstacked DataFrame is too big, causing int32 overflow Any suggestions on solving this problem? Thanks! r_matrix = df.pivot_table(values='rating', index='userId', columns='movieId') 回答1: An integer overflow inside library code is nothing you can do much about. You have basically three options: Change the input data you

问题 I am currently doing the Go Lang tutorial, "Numeric Constants" to be precise. The example code starts with the following statement: const ( // Create a huge number by shifting a 1 bit left 100 places. // In other words, the binary number that is 1 followed by 100 zeroes. Big = 1 << 100 // Shift it right again 99 places, so we end up with 1<<1, or 2. Small = Big >> 99 ) The constant Big is obviously huge, and I am trying to print it and its type, like this: fmt.Printf("%T", Big) fmt.Println

问题 I am currently doing the Go Lang tutorial, "Numeric Constants" to be precise. The example code starts with the following statement: const ( // Create a huge number by shifting a 1 bit left 100 places. // In other words, the binary number that is 1 followed by 100 zeroes. Big = 1 << 100 // Shift it right again 99 places, so we end up with 1<<1, or 2. Small = Big >> 99 ) The constant Big is obviously huge, and I am trying to print it and its type, like this: fmt.Printf("%T", Big) fmt.Println

问题 I'm pulling numbers from a text file and filling an array of type int with them. I'm inserting the values into the array while looping through the .txt file with those lines of code (where k is the amount of numbers in the .txt file): for (int j = 0; j < k; j++) inputFile >> tab[j]; When the numbers in the text file are less than 2,147,483,647 which is the maximum size of an integer type everything goes smooth. When the number is bigger than this the program as i assume overflows and fails to

问题 I need to deal with a counter that gives me ticks for my application. The counter is 32bits so what i need to know is how to deal with it when it wraps. for example: I have a function that returns a (timestamp + shifttime) and i have another function that will return 1 or 0 depending whether or not the time has elapsed, but there could a possibility that that my counter will wrap how do I deal with this ?. Thanks Thanks a lot for all the responses guys. I will give more detail in this edit. I

问题 I've got two signed integers, and i'd like to subtract them. I need to know if it overflowed. int one; int two; int result = two-one; if (OVERFLOW) { printf("overflow"); } else { printf("no overflow"); } Something like that. Is there a good way to do this? 回答1: Firstly, overflow in signed calculations causes undefined behavior in C. Secondly, forgetting about UB for a second and sticking to the typical overflow behavior of a 2's complement machine: overflow is revealed by the fact that result