c - 动态分配和Matrix.Help me

Question

我的这段代码有问题。我必须使用动态分配来计算转置矩阵。该代码适用于 2x2 矩阵，但当我增加矩阵的大小(如 3x3)时，它会失败。有人可以帮助我吗？

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

#define LINE 2
#define COLUMN 2


int** createMat(int line,int colum);
void printMat(int **m, int line,int colum);
void assignMat(int **m, int line, int colum);
int** copyMat(int **m, int line, int colum);
int** traspMat(int **m, int line, int colum);

int main(int argc, char **argv){
    int line = LINE;
    int colum = COLUMN;
    int **matrix;
    int **copy_matrix;
    int **trasp_matrix;
    matrix = createMat(line, colum);
    printf("Pre-Assign\n");
    printMat(matrix, line, colum);
    assignMat(matrix, line, colum);
    printf("After-Assign\n");
    printMat(matrix, line, colum);
    copy_matrix = copyMat(matrix, line, colum);
    printf("Matrix Copied\n");
    printMat(copy_matrix, line, colum);
    trasp_matrix = traspMat(matrix, line, colum);
    printf("Transposed matrix\n");
    printMat(trasp_matrix, line, colum);
    free(matrix);
    free(copy_matrix);
    free(trasp_matrix);
    return 0;
}

int** createMat(int line,int colum){
    int **m = (int**)malloc(line * sizeof(int));
    for(int i = 0; i < line; i++){
        m[i] = (int*)malloc(colum * sizeof(int));
    }
    return m;
 }

 void printMat(int **m, int line,int colum){
    for(int i = 0; i < line; i++){
        for(int j = 0; j < colum; j++){
            printf("%d  ", m[i][j]);
        }
        printf("\n");
    }
}

void assignMat(int **m, int line, int colum){
    printf("Inserisci i valori nella matrice (per riga)\n");
    for (int i = 0; i < line; i++){
        for(int j = 0; j < colum; j++){
            printf("> ");
            scanf(" %d", &m[i][j]);
        }
    }
    printf("\n");
}

int** copyMat(int **m, int line, int colum){
    int **new_mat = createMat(line, colum);
    for(int i = 0; i < line; i++){
        for(int j = 0; j < colum; j++){
            new_mat[i][j] = m[i][j];
        }
    }
    return new_mat;
}

int** traspMat(int **m, int line, int colum){
    int **new_m = createMat(line, colum);
    for(int i = 0; i < line; i++){
        for(int j = 0; j < colum; j++){
            new_m[i][j] = m[j][i];
        }
    }
    return new_m;
}

Answer 1

请注意，malloc(line * sizeof(int))分配line个整数，而不是line 指针的数量。如果 sizeof(int) != sizeof(int*) 那么你就有大麻烦了。 – 一些程序员家伙

使用int **m = malloc(line * sizeof(*m));来代替。 – RoadRunner