C语言 变量警告设置但未使用
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Variable warning set but not used
提问by user3661531
int none[5];
int ntwo[5];
(the following is in a switch statement);
if (answer == userAnswer)
{
printf("Correct!\n");
score = prevScore + 1;
prevScore = score;
}
else
{
printf("Incorrect. The correct answer was %d\n\n", answer);
none[i] = number1;
ntwo[i] = number2;
}
}
break;
(Switch statement ends)
（switch语句结束）
It gives me an error saying "Variable warning "none" set but not used". I have clearly used it. I dont know why this error i happening. FYI all the other variables you see have been declared. I just took out the imp part where the array appears.
它给了我一个错误，说“变量警告“无”设置但未使用”。我已经清楚地使用了它。我不知道为什么我会发生这个错误。仅供参考，您看到的所有其他变量都已声明。我只是取出了数组出现的imp部分。
回答by Mike
noneshows up twice in this code snippet:
none在此代码片段中出现两次：
int none[5]; // declared, not set to anything
And then:
进而：
none[i] = number1; // a value has been set, but it's not being used for anything
If, for example, you later had:
例如，如果您后来有：
int foo = none[3]; // <-- the value in none[3] is being used to set foo
or
或者
for(int i = 0; i < 5; i++)
printf("%d\n", none[i]); // <-- the values in none are being used by printf
or something to that effect, we would say noneis "used", but as the code is, you have: "none" set but not used; exactly what the compiler said.
或者诸如此类的话，我们会说none是“拿来主义”，但作为代码，您有："none" set but not used; 正是编译器所说的。
In the pastebin linkI see your problem:
在pastebin 链接中，我看到了您的问题：
You wrote this:
你写了这个：
for(i=0;i<5;i++)
{
printf("Question [i]: none[i]+ntwo[i]");
You meant to write this:
你打算写这个：
for(i=0;i<5;i++)
{
printf("Question [i]: ", none[i]+ntwo[i]);
Now noneis being used and your print is doing something useful...
现在none正在使用并且您的打印正在做一些有用的事情......
回答by Antoine C.
Using a variable is different from initializing it.
使用变量与初始化变量不同。
Here you set a value to the none variable, but your compiler will tell you it's unused because you never test it with comparison operators, or you never pass it to a function.
在这里，您为 none 变量设置了一个值，但是您的编译器会告诉您它未使用，因为您从未使用比较运算符对其进行测试，或者您从未将其传递给函数。
