Find a 5 respectively × 5 the sum of all rows, columns and elements on two diagonal lines of the matrix. (the input data is inconsistent with the output data)

Direct calculation with formula ：

#include<stdio.h>#define M 2int main(){ int i,j,a[i][j],sum,sum1,sum2; sum=sum1=sum2=0; printf(" Please enter each element of the matrix ：\n"); for(i=0;i<M;i++){ for(j=0;j<M;j++){ scanf("%d",&a[i][j]); } } printf(" The input matrix elements are ：\n"); for(i=0;i<M;i++){ for(j=0;j<M;j++){ printf("%d,",a[i][j]); } printf("\n"); } for(i=0;i<M;i++){ sum=0; for(j=0;j<M;j++){ sum+=a[i][j]; } a[i][j]=sum; printf("%d",a[i][j]); } for(i=0,j=0;i<M;i++,j++) sum1+=a[i][j]; for(i=0,j=0;i>M;i--,j++) sum2+=a[i][j]; printf(" The sum of the elements on the main diagonal is :%d\n The sum of the elements on the diagonal is :%d\n",sum1,sum2);}

give the result as follows ：
Please enter each element of the matrix ：
1 1 1 1
The input matrix elements are ：
1,1,
1,1,
23 The sum of the elements on the main diagonal is :3
The sum of the elements on the diagonal is :0