Find the number that has only appeared once (find out single dogs)
Tip: Use the bitwise XOR operator to quickly find a single number. The XOR of two identical numbers is zero, and the XOR of zero and any number is any number.
#include<stdio.h>
int main()
{
//其他数都是成对出现，只有一个数出现了一次，请找出他
int array[5] = {
1, 1, 3,3,7 };
int i = 0;
int ret = 0;
while (i < 5)
{
ret = ret^array[i];//1^1=0,3^3=0,0^7=7
i = i + 1;
}
printf("单身狗是%d\n", ret);
}