Consider an example of 4 X 4 matrix

1 2 3 4

5 6 7 8

9 0 11 12

13 14 15 16

Then the lower right triangle will be

4

7 8

0 11 12

13 14 15 16

A lower right triangular matrix will print the values of following locations

[0,3]

[1,2] [1,3]

[2,1] [2,2] [2,3]

[3,0] [3,1] [3,2] [3,3]

At first row we need to print 1 item and in 2nd row 2 items and so on. So, in the code we have used one condition at line 34 if(col-j<=i+1), which will check the index of the column that we need to print.

At First Iteration

i = 0 and j = 0 to 3<4 and incremented by 1 and number of col is 4

j = 0, col-0<=1, false

j = 1, col-1<=1, false

j = 2, col-2<=1, false

j = 3, col-3<=1, true print mat of [0][3]

At Second Iteration

i = 1 and j = 0 to 3<4 and incremented by 1 and number of col is 4

j = 0, col-0<=2, false

j = 1, col-1<=2, false

j = 2, col-2<=2, true print mat of [1][2]

j = 3, col-3<=2, true print mat of [1][3]

At Third Iteration

i = 2 and j = 0 to 3<4 and incremented by 1 and number of col is 4

j = 0, col-0<=3, false

j = 1, col-1<=3, true print mat of [2][1]

j = 2, col-2<=3, true print mat of [2][2]

j = 3, col-3<=3, true print mat of [2][3]

At last Iteration

i = 3 and j = 0 to 3<4 and incremented by 1 and number of col is 4

j = 0, col-0<=4, true print mat of [3][0]

j = 1, col-1<=4, true print mat of [3][1]

j = 2, col-2<=4, true print mat of [3][2]

j = 3, col-3<=4, true print mat of [3][3]