b******n
发帖数: 823 | 1 很简单的code，里面有这段
if (j+1 < u)
{
blabla...
}
从watch里面看到j+1是小于u的，但是就是不进这个if
结果改成这样就进去了
int tmp = j+1-u;
if (tmp < 0)
{
blabla...
}
有人知道是啥毛病么？用的VS2008，默认设置，optimization是disable的 |
X****r
发帖数: 3557 | 2 One possibility is that j is signed but u is unsigned.
When a binary operator has both signed and unsigned operands,
the signed integer is converted to unsigned according to
"usual arithmetic conversions". Thus the result of expression
-1 < 1u is false, while -1 < 1 is true. VC should have given
you a warning about mixing signed and unsigned, which you probably
have ignored.
【在 b******n 的大作中提到】
: 很简单的code，里面有这段
: if (j+1 < u)
: {
: blabla...
: }
: 从watch里面看到j+1是小于u的，但是就是不进这个if
: 结果改成这样就进去了
: int tmp = j+1-u;
: if (tmp < 0)
: {
|
b******n
发帖数: 823 | 3 Thanks. But just checked, both are int...
【在 X****r 的大作中提到】
: One possibility is that j is signed but u is unsigned.
: When a binary operator has both signed and unsigned operands,
: the signed integer is converted to unsigned according to
: "usual arithmetic conversions". Thus the result of expression
: -1 < 1u is false, while -1 < 1 is true. VC should have given
: you a warning about mixing signed and unsigned, which you probably
: have ignored.
|
d****p
发帖数: 685 | 4 You may turn off optimization and try rebuild your program. |
l***g
发帖数: 1035 | 5 (j+1)
【在 b******n 的大作中提到】
: 很简单的code，里面有这段
: if (j+1 < u)
: {
: blabla...
: }
: 从watch里面看到j+1是小于u的，但是就是不进这个if
: 结果改成这样就进去了
: int tmp = j+1-u;
: if (tmp < 0)
: {
|
