# Golang Program To Interchange Elements Of First And Last In A Matrix Across Rows

In this article, we will write a go language program to interchange elements of first and last row in a matrix.

## Interchange Elements Of The First And Last Row In A Matrix Using An External Function

In this program, we will write a go language program to interchange the elements of the first and last row of a 3 X 3 matrix using an external function.

### Algorithm

Step 1 − Import the fmt package.

Step 2 − Create a function to interchange the first and last row of a matrix. In this function, we have defined two variables of integer type and assigned values to them.

Step 3 − Use for loop to iterate over the matrix elements and store each element temporarily in the t variable initialized above.

Step 4 − Now, store the elements of the last row in place of first one and store back the value stored in temporarily variable to the last row.

Step 5 − Repeat these processes until whole rows values are interchanged.

Step 6 − Now, start the main() function. Here, initialized a 3 X 3 matrix and print it on the screen.

Step 7 − Call the matrixInter() function by passing the matrix as argument to the function.

Step 8 − Now, print the matrix on the screen using for loops and fmt.Println() function.

### Example

package main
import "fmt"

// function to interchange rows
func matrixInter(mat [][]int) {
var t int = 0
var rows int = 3
for i := 0; i < 3; i++ {
t = mat[0][i]
mat[0][i] = mat[rows-1][i]
mat[rows-1][i] = t
}
}
func main() {
mat := [][]int{
{10, 1, 2},
{4, 5, 6},
{8, 9, 10},
}
fmt.Println("The given matrix is: \n")
for i := 0; i < 3; i++ {
for j := 0; j < 3; j++ {
fmt.Print(mat[i][j], "\t")
}
fmt.Println()
}
fmt.Println()
matrixInter(mat)
fmt.Println("The matrix obtained after interchanging first and last row is: \n")
for i := 0; i < 3; i++ {
for j := 0; j < 3; j++ {
fmt.Print(mat[i][j], "\t")
}
fmt.Println()
}
}

### Output

The given matrix is:

10	1	2
4	5	6
8	9	10

The matrix obtained after interchanging first and last row is:

8	9	10
4	5	6
10	1	2

## Interchange The First And Last Row Of A Matrix Of Order 4 Or Above

In this program, we will see that how we can interchange the elements of top and bottom rows of a matrix of order 4 or above.

### Algorithm

Step 1 − Import the fmt package.

Step 2 − Now, start the main() function. Here, initialize a 3 X 3 matrix and print it on the screen.

Step 3 − Define two variables of integer type and assign values to them. Use for loop to iterate over the matrix elements and store each element temporarily in the t variable initialized above.

Step 4 − Now, store the elements of last row in place of first one and store back the value stored in temporarily variable to the last row.

Step 5 − Repeat these processes until whole rows values are interchanged.

Step 6 − Now, print the matrix on the screen using for loops and fmt.Println() function.

### Example

package main
import "fmt"

// calling the main() function
func main() {
mat := [][]int{
{8, 9, 7, 6},
{4, 7, 6, 5},
{3, 2, 1, 8},
{9, 9, 7, 7},
}
fmt.Println("The given matrix is: \n")
for i := 0; i < 4; i++ {
for j := 0; j < 4; j++ {
fmt.Print(mat[i][j], "\t")
}
fmt.Println()
}
fmt.Println()
var t int = 0
var rows int = 4
for i := 0; i < 4; i++ {
t = mat[0][i]
mat[0][i] = mat[rows-1][i]
mat[rows-1][i] = t
}
fmt.Println("The matrix obtained after interchanging first and last row is: \n")
for i := 0; i < 4; i++ {
for j := 0; j < 4; j++ {
fmt.Print(mat[i][j], "\t")
}
fmt.Println()
}
}

### Output

The given matrix is:

8	9	76
4	7	6	5
3	2	1	8
9	9	7	7

The matrix obtained after interchanging first and last row is:

9	9	7	7
4	7	6	5
3	2	1	8
8	9	7	6

## Conclusion

We have successfully compiled and executed a go language program to interchange the elements of first and last rows of a matrix along with examples. In the first example, we have used the logic to interchange elements of a 3 X 3 matrix while in the second one we are extending the logic to matrices of the order 4 or above.

Updated on: 02-Jan-2023

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