无符号整型与有符号整型相运算规则

有符号数和无符号数运算的时候，有符号数会自动向无符号数转换

#include<iostream>
#include<ctime>
#include <stdio.h>
#include<cstring>
#include<cstdlib>
#include <map>
#include <string>
using namespace std;

#if TEST
int main(){
    int a = -3;
    unsigned int b = 2;
    int c = a+b;
    printf("c:%u
", c);
    printf("c:%d
", c);
    int x = -3;
    unsigned int y = 2;
    unsigned int z = x+y;
    printf("z:%u
", z);
    printf("z:%d
", z);
}
#endif

u c:4294967295
d c:-1
z:4294967295
z:-1