WAP for sum of elements in matrix

#include<iostream.h>

#include<conio.h>

void main()

{

 int a[5][5],n,m,i,j,small;

 int sum=0;

 cout<<"\n enter size of rows :";

 cin>>n;

 cout<<"\n enter size of collumns  :";

 cin>>m;

 cout<<"\n enter element of 2d array :";

for(i=1;i<=n;i++)

{

for(j=1;j<=m;j++)

{

cin>>a[i][j];

}

}

 cout<<"\n 2d array \n\n\n:";

for(i=1;i<=n;i++)

{

for(j=1;j<=m;j++)

{

cout<<"\t"<<a[i][j];

}

cout<<"\n";

}

for(i=1;i<=n;i++)

{

for(j=1;j<=m;j++)

{

sum=sum+a[i][j];

}

cout<<"\n";

}

cout<<"\n The sum of every element :"<<sum;

 getch();

 clrscr();

 }