Answer
code
Work Step by Step
# 8.2 (Check substrings) You can check whether a string is a substring of another string
# by using the find method in the str class. Write your own function to implement
# find. Write a program that prompts the user to enter two strings and then checks
# whether the first string is a substring of the second string.
def main():
s1 = input("First string: ")
s2 = input("Second string: ")
f = find(s1, s2)
if f == -1:
print(s1, "is not substring of", s2)
else:
print(s1, "is substring of", s2, "at index", f)
def find(s1, s2):
l1 = len(s1)
l2 = len(s2)
start = 0
while l1 <= l2:
if s1 != s2[start:start + l1]:
start += 1
l2 -= 1
else:
return start
return -1
main()
