9626. startsWith endsWith

Three lines of characters is given. Check if the second line is a prefix of the first line. Check if the third line is a suffix of the first line.

Input. Three lines, each contains no more than 100 characters.

Output. In the first line print true or false depending on whether second line is a prefix of the first one. In the second line print true or false depending on whether third line is a suffix of the first one.

Sample input	Sample output
qwerty qwe ty	true true

SOLUTION

strings

Algorithm analysis

Function

char *strstr(const char *haystack, const char *needle)

finds the first occurrence of the substring needle in the string haystack. 

String b is a prefix of a if b appears in a starting at position 0.

String c is a suffix of a if c appears in a starting at position

a + strlen(a) – strlen(c)

Algorithm realization

Declare three char arrays.

char a[101], b[101], c[101];

Read three input strings.

gets(a);

gets(b);

gets(c);

String b is a prefix of a if b appears in a starting at position 0.

if (strstr(a, b) == a)

puts("true");

else

puts("false");

String c is a suffix of a if c appears in a starting at position a + strlen(a) – strlen(c).

if (strstr(a + strlen(a) - strlen(c), c) == a + strlen(a) - strlen(c))

puts("true");

else

puts("false");

Algorithm realization – С++

#include <iostream>

#include <string>

using namespace std;

string a, b, c;

int len;

int main()

{

cin >> a >> b >> c;

if (a.substr(0, b.size()) == b)

puts("true");

else

puts("false");

if (a.substr(a.size() - c.size(), c.size()) == c)

puts("true");

else

puts("false");

return 0;

}

Java realization

import java.util.*;

public class Main

{

public static void main(String[] args)

{

Scanner con = new Scanner(System.in);

String s = con.nextLine();

if (s.startsWith(con.nextLine()))

System.out.println("true"); else System.out.println("false");

if (s.endsWith(con.nextLine()))

System.out.println("true"); else System.out.println("false");

con.close();

}

}

Python realization

s = input()

start = input()

end = input()

if s.startswith(start):

print("true")

else:

print("false")

if s.endswith(end):

print("true")

else:

print("false")