[已解决]malloc was not declared in this scope

18856966759

红色的地方编译有错误，不知道哪里有问题
#include <stdio.h>
#define MAXSIZE 5
typedef int ElementType;
typedef int Position;
typedef struct LNode *List;
struct LNode{
        ElementType data[MAXSIZE];
        Position Last;/*保存数组Data[]中最后一个元素的位置*/
};


Position BinarySearch(List, ElementType);
int main()
{
        List L;
        L = (List)malloc(sizeof(struct LNode));
        L->data        = {12, 31, 55, 89, 101};
        L->Last = sizeof(L->data);
        ElementType X = 31;
        Position ret;
        ret = BinarySearch(L, X);
        printf("%d is %d", X, ret);
        return 0;
}

Position BinarySearch(List L, ElementType X)
{
        Position Left, Right, Mid;
       
        Left = 1;
        Right = L->Last;
        while(Left <= Right)
        {
                Mid = (Left + Right) / 2;
                if(L->data [Mid] > X)
                        Right = Mid - 1;
                else if(L->data [Mid] < X)
                        Left = Mid + 1;
                else
                        return Mid;
        }
}

最佳答案

月排行榜 / 总排行榜

superbe

2019-12-13 12:17:28

少头文件了吧#include <malloc.h>
BinarySearch的逻辑有点问题，修改的代码：

1. #include <stdio.h>
   
2. #include <malloc.h>
   
3. #define MAXSIZE 5
   
4. typedef int ElementType;
   
5. typedef int Position;
   
6. typedef struct LNode *List;
   
7. struct LNode {
   
8.     ElementType data[MAXSIZE];
   
9.     Position Last;
   
10. };
    
11. 
    
12. Position BinarySearch(List, ElementType);
    
13. int main()
    
14. {
    
15.     List L;
    
16.     L = (List)malloc(sizeof(struct LNode));
    
17.     //L->data = { 12, 31, 55, 89, 101 };
    
18.     L->data[0] = 12;
    
19.     L->data[1] = 31;
    
20.     L->data[2] = 55;
    
21.     L->data[3] = 89;
    
22.     L->data[4] = 101;
    
23. 
    
24.     L->Last = sizeof(L->data) / sizeof(ElementType);
    
25.     ElementType X = 31;
    
26.     Position ret;
    
27.     ret = BinarySearch(L, X);
    
28.     (ret > 0) ? printf("%d is %d\n", X, ret) : printf("Not found\n");
    
29.     return 0;
    
30. }
    
31. 
    
32. Position BinarySearch(List L, ElementType X)
    
33. {
    
34.     Position Left, Right, Mid;
    
35. 
    
36.     Left = 1;
    
37.     Right = L->Last;
    
38.     while (Left <= Right)
    
39.     {
    
40.         Mid = (Left + Right) / 2;
    
41.         if (L->data[Mid - 1] == X)
    
42.             return Mid;
    
43.         if (L->data[Mid - 1] > X)
    
44.             Right = Mid - 1;
    
45.         else if (L->data[Mid - 1] < X)
    
46.             Left = Mid + 1;
    
47.     }
    
48.     return -1;
    
49. }

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superbe

少头文件了吧#include <malloc.h>
BinarySearch的逻辑有点问题，修改的代码：

1. #include <stdio.h>
   
2. #include <malloc.h>
   
3. #define MAXSIZE 5
   
4. typedef int ElementType;
   
5. typedef int Position;
   
6. typedef struct LNode *List;
   
7. struct LNode {
   
8.     ElementType data[MAXSIZE];
   
9.     Position Last;
   
10. };
    
11. 
    
12. Position BinarySearch(List, ElementType);
    
13. int main()
    
14. {
    
15.     List L;
    
16.     L = (List)malloc(sizeof(struct LNode));
    
17.     //L->data = { 12, 31, 55, 89, 101 };
    
18.     L->data[0] = 12;
    
19.     L->data[1] = 31;
    
20.     L->data[2] = 55;
    
21.     L->data[3] = 89;
    
22.     L->data[4] = 101;
    
23. 
    
24.     L->Last = sizeof(L->data) / sizeof(ElementType);
    
25.     ElementType X = 31;
    
26.     Position ret;
    
27.     ret = BinarySearch(L, X);
    
28.     (ret > 0) ? printf("%d is %d\n", X, ret) : printf("Not found\n");
    
29.     return 0;
    
30. }
    
31. 
    
32. Position BinarySearch(List L, ElementType X)
    
33. {
    
34.     Position Left, Right, Mid;
    
35. 
    
36.     Left = 1;
    
37.     Right = L->Last;
    
38.     while (Left <= Right)
    
39.     {
    
40.         Mid = (Left + Right) / 2;
    
41.         if (L->data[Mid - 1] == X)
    
42.             return Mid;
    
43.         if (L->data[Mid - 1] > X)
    
44.             Right = Mid - 1;
    
45.         else if (L->data[Mid - 1] < X)
    
46.             Left = Mid + 1;
    
47.     }
    
48.     return -1;
    
49. }

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