结构体矩阵输出时乱码

Question

#include<bits/stdc++.h>
using namespace std;
struct Matrix
{
    int height,width;
    int** m;
    Matrix createZeroMatrix(int h,int w)
    {
        Matrix m1;
        m1.height=h;
        m1.width=w;
        m1.m=new int* [h];
        for(int i=0; i<h; i++)
        {
            m1.m[i]=new int[w];
            memset(m1.m[i],0,sizeof(*m1.m[i]));
        }
       return m1;
    }
    Matrix multiply(Matrix A,Matrix B)
    {
        Matrix m1=createZeroMatrix(A.height,B.width);
        for(int i=0; i<A.height; i++)
            for(int j=0; j<B.width; j++)
                for(int k=0; k<A.width; k++)
                {
                    m1.m[i][j]+=A.m[i][k]*B.m[k][j];
                }
        return m1;
   }
};
int main()
{
    Matrix m1=m1.createZeroMatrix(5,5);
    //Matrix m2=m2.createZeroMatrix(5,5);
    //Matrix m3=m3.multiply(m1,m2);
    for(int i=0; i<m1.height; i++)
    {
        for(int j=0; j<m1.width; j++)
        {
            printf("%d ",m1.m[i][j]);
        }
        printf("\n");
    }
    return 0;
}

Answer 1

memset(m1.m[i],0,w*sizeof(*m1.m[i]));
另外你这个create函数不需要这么写，直接给所在结构创建空间不就行了么。如下修改：

#include <bits/stdc++.h>
using namespace std;
struct Matrix
{
    int height, width;
    int **m;
    Matrix(int h,int w)
    {
          createZeroMatrix(h,w);
    }
    void createZeroMatrix(int h, int w)
    {
        height = h;
        width = w;
        m = new int *[h];
        for (int i = 0; i < h; i++)
        {
            m[i] = new int[w];
            memset(m[i], 0, sizeof(int)*w);
        }
    }
    Matrix multiply(Matrix A)
    {
        Matrix m1(height, A.width);
        for (int i = 0; i < height; i++)
            for (int j = 0; j < A.width; j++)
                for (int k = 0; k < width; k++)
                {
                    m1.m[i][j] += m[i][k] * A.m[k][j];
                }
        return m1;
    }
};
int main()
{
    Matrix m1(5, 5);
    for (int i = 0; i < m1.height; i++)
    {
        for (int j = 0; j < m1.width; j++)
        {
            printf("%d ", m1.m[i][j]);
        }
        printf("\n");
    }
    return 0;
}