Find out the number of 1 in an integer

Enter an integer to find the number of binary 1. Consider the point of knowledge: How to ask for negative numbers, because the computer is stored in a complement of the form of storing a number. Because positive source code, anti-code, complement are the same, do not consider. But negative numbers will have to be considered, such as-0, its source code should be 10000000 00000000 00000000 000000000 00000000, so negative numbers to consider.

Here is the code implementation:

#ifndef  _findnumberof1_#define _findnumberof1_/*================================ macros == =================================*/#define  false 0#define ture 1/*======================== ========&NBSP;FUNCTION&NBSP;===================================*/INT&NBSP;FINDNUMBEROF1 (int num); #endif  //_findnumberof1_ /***********************************************************//*32 bit Platform *//* Function Name: findnumberof1*//* functions Port parameter: integer *//* function return value requiring 1: Returns the number of 1 or the error code *//* function: The number of binary 1 in the input integer *//******************************** /int findnumberof1 (Int num) {         int retvalue = 0;if ( -0 == num)   {return 1;} Else if (num >= 0) {while (num) {if (1 ==  (num&1)) {retvalue++;} num >>= 1;}} else{num =  (~num+1);//negative numbers are stored in a complementary fashion, so source while (num) {if (1 ==  (num&1)) {retvalue++;} num >>= 1;} Retvalue += 1;//plus sign bit}        return retvalue;} #include <stdio.h> #include "findNumberOf1.h" Static int inputnumber (int *number) {if (NULL  == number) {return false;} printf ("Please enter an integer:"); scanf ("%d", number), if ((number < -2147483648) && (number>2147483647)) { printf ("Number of inputs out of range \ n"); return false;}} /***********************************************************//*32 bit platform *//* function name: main*//* function Port parameter: No *//* function return value: 0*//* function function: program null *//***********************************************************/int main () {int number =  0;int returnvalue = 0;inputnumber (&number); Returnvalue = findnumberof1 ( Number);p rintf ("%d", returnvalue);p rintf ("\ n"), System ("pause"); return 0;}

Find out the number of 1 in an integer