從 C 中的函數返回 malloc

Question

我已經嘗試從函數返回 malloc 三天了，但沒有任何樂趣。

我的代碼如下我想要做的是傳遞兩個一維數組並執行矩陣計算，然后在二維數組中返回結果。 代碼如下：

int **func1(numrow, numcol, *temp, *word){

int  i, c, d;
int **pointer;

pointer = (int**)malloc( numrow * sizeof(int*);

        for(i=0; i<numrow; i++){
           pointer[i] = (int*)malloc( numcol * sizeof(int*) );    
        }

        for ( c = 0 ; c < numrow ; c++ )
            for ( d = 0 ; d < numcol ; d++ )
                    pointer[c][d] =( (temp[c] - word[r]) * (temp[c] - word[r])     );   

    return pointer;

}

int main(){

int **poi, r, c, numcol, numrow;
int templet[8] = {1, 1, 1, 1, 3, 4, 4, 4 };
int newWord[8] = {1, 1, 4, 4, 4, 5, 0, 0 };

printf("please enter the number of rows:\n");
scanf("%d%d",&numrow, &numcol);

    poi = func1(numrow, numcol, templet, newWord );


        for(r=0; r<numrow; r++)
            for(c=0; c< numrow; c++)

                printf("%d\n",*(*(poi + r) + c));


return 0;
}

Answer 1

首先將您的函數聲明符更改為

int **func1(int numrow, int numcol, int *temp, int *word)

然后用d替換r

pointer[c][d] =( (temp[c] - word[r]) * (temp[c] - word[r]));   

最后

printf("%d\n",*(*(poi + r) + c));

到

printf("%d\n",poi[r][c]);    

更正的代碼：

int **func1(int numrow, int numcol, int *temp, int *word) {

int  i, c, d;
int **pointer;

pointer = malloc(numrow * sizeof(int*));

    for (i = 0; i < numrow; i++){
       pointer[i] = malloc(numcol * sizeof(int));
    }

    for ( c = 0 ; c < numrow ; c++ )
        for ( d = 0 ; d < numcol ; d++ )
                pointer[c][d] =( (temp[c] - word[d]) * (temp[c] - word[d]));

    return pointer;
}

int main(void){
    int **poi, r, c, numcol, numrow;
    int templet[8] = {1, 1, 1, 1, 3, 4, 4, 4 };
    int newWord[8] = {1, 1, 4, 4, 4, 5, 0, 0 };

    printf("please enter the number of rows and columns:\n");
    scanf("%d%d", &numrow, &numcol);
    poi = func1(numrow, numcol, templet, newWord);
    for (r = 0; r < numrow; r++)
        for(c = 0; c  numrow; c++)
            printf("%d\n",poi[r][c]);
        return 0;
}  

---

可能的建議：

• 學習正確縮進代碼。
• 在這里詢問之前，請盡可能多次調試您的代碼。
• 打開編譯器警告（如-Werror 、 -pedantic等）。

Answer 2

您的代碼完整代碼中所需的小改動如下：

#include <stdio.h>
#include <stdlib.h>

int **func1(int numrow, int numcol, int *temp, int *word){  
    int  i, c, d;
    int **pointer;

    pointer = (int**)malloc( numrow * sizeof(int*));

    for(i=0; i<numrow; i++){
        pointer[i] = (int*)malloc( numcol * sizeof(int*) );    
    }

    for ( c = 0 ; c < numrow ; c++ ){
        for ( d = 0 ; d < numcol ; d++ ){
            pointer[c][d] =( (temp[c] - word[d]) * (temp[c] - word[d])     );
        }
    }
    return pointer;
}

int main(){

    int **poi, r, c, numcol, numrow;
    int templet[8] = {1, 1, 1, 1, 3, 4, 4, 4 };
    int newWord[8] = {1, 1, 4, 4, 4, 5, 0, 0 };

    printf("please enter the number of rows:\n");
    scanf("%d%d",&numrow, &numcol);

    poi = func1(numrow, numcol, templet, newWord );


        for(r=0; r<numrow; r++){
            for(c=0; c< numrow; c++){
                printf("%d\n",poi[r][c]); 
            }
        }
    return 0;
}