c – 整数溢出错误

这是我的OpenGL代码的一部分,我得到一个错误：

struct Ball {
    float x;
    float y;
    float rot;
    float dir;
    bool rmv;
    Ball* next;
};

Ball* curBall;
void addBall() {
    if (balls==NULL) {
        balls=new Ball;
        balls->next=NULL;
        curBall=balls;
    } else {
        curBall->next=new Ball;
        curBall=curBall->next;
        curBall->next=NULL;
    }
    curBall->x=((float)rand()/(float)(RAND_MAX+1))*(ww-1) +1;
    curBall->y=((float)rand()/(float)(RAND_MAX+1))*(wh-1) +1;
    curBall->dir=((float)rand()/(float)(RAND_MAX+1))*(2*PI-1) +1;
    curBall->rot=((float)rand()/(float)(RAND_MAX+1))*(359) +1;
    curBall->rmv=false;
}

error :
In function ‘void addBall()’:
file.cpp:120: warning: integer overflow in expression
file.cpp:121: warning: integer overflow in expression
file.cpp:122: warning: integer overflow in expression
file.cpp:123: warning: integer overflow in expression

解决方法

尝试在添加之前将RAND_MAX转换为浮点数.

curBall->x=((float)rand()/( ((float)RAND_MAX) +1))*(ww-1) +1;

等等. RAND_MAX通常等于INT_MAX,这是整数可以容纳的最大值,因此在它仍被视为整数时将其加1会将其推到整数限制之上.