significant-digits

NB : this question is about significant figures . It is not a question about "digits after the decimal point" or anything like that. EDIT : This question is not a duplicate of Significant figures in the decimal module . The two questions are asking about entirely different problems. I want to know why the function about does not return the desired value for a specific input. None of the answers to Significant figures in the decimal module address this question. The following function is supposed to return a string representation of a float with the specified number of significant figures:

I want to extract the n most significant bits from an integer in C++ and convert those n bits to an integer. For example int a=1200; // its binary representation within 32 bit word-size is // 00000000000000000000010010110000 Now I want to extract the 4 most significant digits from that representation, i.e. 1111 00000000000000000000010010110000 ^^^^ and convert them again to an integer (1001 in decimal = 9). How is possible with a simple c++ function without loops? Mike Seymour Some processors have an instruction to count the leading binary zeros of an integer, and some compilers have

How can I do math involving significant figures in C++? I want this to work correct with measured data from chemistry and physics experiments. An example: 65 / 5 = 10. I would need to get rid of unneeded decimal places and replace some digits with 0s. Thanks! Well there are good math libraries in math.h Also storing your figures in floats, doubles or long doubles will allow for more precise operations. Floats offer 7 significant digits while doubles offer 16 significant digits. source Also when printing out usually people use _snprintf or printf and you can format those doubles, floats to the

In Xcode /Objective-C for the iPhone. I have a float with the value 0.00004876544. How would I get it to display to two decimal places after the first significant number? For example, 0.00004876544 would read 0.000049. Nate Thorn I didn't run this through a compiler to double-check it, but here's the basic jist of the algorithm (converted from the answer to this question ): -(float) round:(float)num toSignificantFigures:(int)n { if(num == 0) { return 0; } double d = ceil(log10(num < 0 ? -num: num)); int power = n - (int) d; double magnitude = pow(10, power); long shifted = round(num*magnitude)

I am using excel and i want to display a value to a certain number of significant figures. I tried using the following equation =ROUND(value,sigfigs-1-INT(LOG10(ABS(value)))) with value replaced by the number I am using and sigfigs replaced with the number of significant figures I want. This formula works sometimes, but other times it doesn't. For instance, the value 18.036, will change to 18, which has 2 significant figures. The way around this is to change the source formatting to retain 1 decimal place. But that can introduce an extra significant figure. For instance, if the result was 182