Program to print last 10 lines

Given some text lines in one string, each line is separated by ‘\n’ character. Print the last ten lines. If number of lines is less than 10, then print all lines. Source: Microsoft Interview | Set 10 Following are the steps 

1) Find the last occurrence of DELIM or '\n' 

2) Initialize target position as last occurrence of '\n' and count as 0 , and do following while count < 10

2.a) Find the next instance of '\n' and update target position

2.b) Skip '\n' and increment count of '\n' and update target position 3) Print the sub-string from target position. 

Output:

str16
str17
str18
str19
str20
str21
str22
str23
str24
str25
-----------------
str1
str2
str3
str4
str5
str6
str7
-----------------

-----------------
ERROR: string doesn't contain '\n' character
-----------------

Time Complexity: O(n)

Auxiliary Space: O(1)

Note: Above program can be modified to print last N lines by passing N instead of 10. N can store any integer value. This article is compiled by Narendra Kangralkar.