Get first col in matrix-CodePudding

I have simple program that gets the sum of main and anti diagonals of a matrix. And then it get the sum of first and last column of a matrix.For example:

1 2 3
4 5 6  --> The matrix
7 8 9

md = 1   5   9 = 15
ad = 7   5   3 = 15
lastCol = 3   6   9 = 18
firstCol = 1   4   7 = 12

How can i get the sum of the firstCol of a square matrix ?
Here is my code:

int main(){
    int n;
        scanf("%d",&n);
        int i,j,a[n][n],firstCol=0,lastCol=0,md=0,ad=0;
        for(i = 0;i <n;i  ){
            for(j=0;j<n;j  ){
                scanf("%d",&a[i][j]);
            }
        }
        for(i = 0;i <n;i  ){
            for(j=0;j<n;j  ){
                if(i==j){
                    md =a[i][j];
                }
                if(i j==n-1){
                    ad =a[i][j];
                }
            }
        }
        for(i=0;i<n;i  ){
                lastCol =a[i][n-1];
        }
}

CodePudding user response：

for (i = 0; i < n; i   ) {
    firstCol  = a[i][0];
}

CodePudding user response：

Use functions. Try to make them a bit more universal. This one will return sum of the first column of any size array.

long long int sumFirstCol(size_t rows, size_t cols, int (*array)[cols])
{
    long long int result = 0;
    if(array && rows && cols)
    {
        for(size_t row = 0; row < rows; row  )
        {
            result  = array[row][0];
        }
    }
    return result;
}

int main(void)
{
    int matrix[3][3] = {
        {1, 2, 3},
        {4, 5, 6},
        {7, 8, 9},};

    printf("%lld\n", sumFirstCol(3, 3, matrix));
}