java - 我需要在 if 语句之外使用 if 语句的输出，但出现错误

Question

你好，我有这段代码，我想在 if 语句中使用变量“mid”，但我不能，因为它是私有(private)的，它只能在较小的 if 语句中使用。

    int mid;
    int high = Math.max(Math.max(R1, G1), B1);
    int low = Math.min(Math.min(R1, G1), B1);
    if (high == R1) {
        if (low == G1)
            mid = B1;
        else
            mid = G1;
        System.out.println("mid is: " + mid);
    } else if (high == G1) {
        if (low == R1)
            mid = B1;
        else
            mid = R1;
        System.out.println("mid is: " + mid);
    } else if (high == B1) {
        if (low == G1)
            mid = R1;
        else
            mid = G1;
        System.out.println("mid is: " + mid);
    }
    System.out.println("High is: " + high);
    System.out.println("low is: " + low);
    int v = high;
    int s;
    int h;
    if (v == 0) {
        s = 0;
        h = 0;
    } else {
        s = (high - low) / high;
        if (s == 0) {
            h = 0;
        } else {
            double alpha;
            alpha = 60 * (mid - low) / (high - low);
        /* problem here in mid variable above, it's not taking the output from if statements */
        }
    }

Answer 1

只需初始化mid。现在问题已解决。

 int mid=0

您当前的代码

 int mid; // not initialize 
 int high = Math.max(Math.max(R1,G1),B1);
 // rest of the code

当您到达最后一个else时，您的mid尚未初始化。