函数参数类型匹配错误

Question

#include <stdio.h>

int fmin(int height1, int height2)
{
    int height = 0;
    if (height1 < height2)
        height = height1;
    else
        height = height2;
    return height;
}

int maxArea(int* height, int heightSize)
{
    int left = 0;
    int right = heightSize - 1;
    int maxAre = 0;
    while (left < right)
    {
        int height = fmin(*(height+left), *(height+right));
        int wide = right - left;
        int are = wide * height;
        if (maxAre < are)
            maxAre = are;
        if (height[left] < height[right])
        {
            left++;
        }
        else
        {
            right--;
        }
    }
    return maxAre;
}

int main()
{
    int height[9] = { 1, 8, 6, 2, 5, 4, 8, 3, 7 };
    int num = maxArea(height, 9);
    printf("%d",num);

    return 0;
}

这个fmin函数为什么没法传某一个索引下的数组的具体值？[Error] invalid type argument of unary '*' (have 'int')

Answer 1

问题在 int maxArea(int* height, int heightSize) 函数里，函数的形参 int* height 是指针变量，但在函数里定义了同名局部变量 int height ，造成错误，修改如下，改动处见注释：

#include <stdio.h>

int fmin(int height1, int height2)
{
    int height = 0;
    if (height1 < height2)
        height = height1;
    else
        height = height2;
    return height;
}

int maxArea(int* Height, int heightSize) //int maxArea(int* height, int heightSize) 修改
{
    int left = 0;
    int right = heightSize - 1;
    int maxAre = 0;
    while (left < right)
    {
        int height = fmin(*(Height + left), *(Height + right)); // int height = fmin(*(height+left), *(height+right)); 修改
        int wide = right - left;
        int are = wide * height;
        if (maxAre < are)
            maxAre = are;
        if (Height[left] < Height[right]) // if (height[left] < height[right]) 修改
        {
            left++;
        }
        else
        {
            right--;
        }
    }
    return maxAre;
}

int main()
{
    int height[9] = { 1, 8, 6, 2, 5, 4, 8, 3, 7 };
    int num = maxArea(height, 9);
    printf("%d", num);

    return 0;
}