关于C中的整数提升，简称

Posted 2021-04-15

void main(){
    char c;
    unsigned char uc;
    unsigned short us1, us2;
    short s1, s2;

    c = 0xf0; uc = 0xf0;
    us1 = c; us2 = uc;
    printf("us1 = %x, 	 us2 = %x
", us1, us2);
    s1 = c; s2 = uc;
    printf("s1 = %x, 	 s2 = %x
", s1, s2);
}

结果：us1 = fff0，us2 = f0 s1 = fffffff0，s2 = f0

s1为什么会这样？即使在32位和sizeof short是2个字节

答案

这是因为short在int的变量参数调用中被提升为printf()。