This question already has an answer here:
这个问题在这里已有答案:
- Undefined reference to `pow' and `floor' 5 answers
未明确引用`pow'和`floor'5答案
I have a codepad .
我有一个键盘。
On line 15 inside a for function
在第15行内的for函数
for(i=2; i<=90; i+=2){
int j=0+i;
printf("%i\n",i);
power=pow(inp,j);
factor=factorial(i);
if(i%4==0)fAns += power/factor;
else fAns -= power/factor;
}
the line power=pow(inp,j); I added j instead of just using i because it gave me the same error. undefined reference to 'pow'.
line power = pow(inp,j);我添加了j而不是仅使用i,因为它给了我同样的错误。未明确引用'pow'。
If I replace j with 2, then it works just fine but when I use j=i it wont work. Is there a problem with incrementing this line?
如果我用2代替j,那么它工作得很好但是当我使用j = i时它不会工作。递增此行是否有问题?
I want this to increment and not throw me an error.
我希望这个增加,而不是给我一个错误。
1 个解决方案
#1
22
You need to link with the math library. With gcc, this would mean passing -lm during linking.
您需要链接数学库。使用gcc,这意味着在链接期间传递-lm。
The reason it doesn't complain when you use 2 as the exponent value is because the compiler is optimizing the pow call out.
当你使用2作为指数值时它没有抱怨的原因是因为编译器正在优化pow调用。
#1
22
You need to link with the math library. With gcc, this would mean passing -lm during linking.
您需要链接数学库。使用gcc,这意味着在链接期间传递-lm。
The reason it doesn't complain when you use 2 as the exponent value is because the compiler is optimizing the pow call out.
当你使用2作为指数值时它没有抱怨的原因是因为编译器正在优化pow调用。