问用于显示显示垃圾值的矩阵元素的C++函数

EN

#include<iostream>
using namespace std;
int i,j;
void getMatrix(int M[100][100])
{
 for(int a=1;a<=i;a++)
  {
    for(int b=1;b<=j;b++) cin>>M[a][b];
  }
}
-------------------------this function----------------------------------------
void showMatrix(int M[100][100])
{
 for(int a=1;a<=i;a++)
  {
    cout<<endl;
    for(int b=1;b<=j;b++) cout<<M[a][b]<<cout<<" ";
  }
}
------------------------------------------------------------------------------
int main()
{
int sum=0;
int m[100][100];
cout<<"Enter matrix dimensions";
cin>>i>>j;
cout<<"Enter Matrix elements\n";
getMatrix(m);
cout<<"Matrix is : ";
showMatrix(m);
for(int n=0;n<=i;n++)sum+=m[n][n];
cout<<"\n sum of diagonal elements is "<<sum;
}