Question

(Longest common prefix, C-string, loop, char comparison)

Write the prefix function to find the longest prefix of two strings using C-strings with the following header:

void prefix( const char s1[ ], const char s2[ ], char commonPrefix[ ])

Write a test program that prompts the user to enter two C-strings and displays their common prefix.

Sample run :- String 1: Programming is fun

String 2: Program logic

The common prefix is program.

Answer 1

Program:

Output:

Editable code:

//Include necessary header files

#include<iostream>

//Declare the namespace

using namespace std;

//Declare the function "prefix()"

void prefix( const char s1[], const char s2[], char commonPrefix[]);

//Define the "main()" function

int main()

{

//Declare the character array

char s1[50];

char s2[50];

char commonPrefix[50];

//Print the statement

cout<<"Enter string1: ";

//Get the first string from the user

cin.getline(s1, 50);

//Print the statement

cout<<"Enter string2: ";

//Get the second string from the user

cin.getline(s2, 50);

//Call the function "prefix()"

prefix(s1, s2, commonPrefix);

//Print the result

cout<<"The common prefix is "<<commonPrefix<<endl;

//Return zero

return 0;

}

//Define the function "prefix()"

void prefix( const char s1[], const char s2[], char commonPrefix[])

{

//Declare and initialize the necessary variables

int a, b, c=0;

//For loop to check the words in the strings

for(a=0, b=0; s1[a]!='\0' && s2[a]!='\0'; a++, b++)

{

//Check the condition

if(s1[a] != s2[b])

//True, break the statement

break;

//Otherwise, assign "s1[a]" to "commonPrefix"

commonPrefix[c++] = s1[a];

}

//Assign null character to "commonPrefix"

commonPrefix[c] = '\0';

}