This solution flow demonstrates step by step right from understanding to build a solution to testing it as well. Learn More: https://bit.ly/2Ex1E6v

1. • Understand the problem
• Write the solution in plain English
• Break the problem into chunks
• Create a flow / write a pseudo-code
• Trace the solution with the test
cases/dry run - define the test
cases
• Write code
• Evaluate - Dry run
Building a near to
ideal solution

2. Problem: Find the longest word in the sentence
Input String : "The cat sat on the mat with another cat"
Step 1 Understanding the problem

3. Problem: Find the longest word in the sentence
To find the longest word we need to accept the
input from the user, and break the sentence
into words. Compare the length of each word
to find the word with the longest length.
Return the longest word as output.
Step 2 Writing the solution in plain English

4. Problem: Find the longest word in the sentence
Step 3 Breaking the problem into chunks
Identifying the pieces of the solution to solve
the problem.
- Take input
- Validate input
- Split the sentence into words
- Compare the length of the words

5. Step 4
Creating
the flow /
writing
pseudocode

6. Step 4 Creating the flow / writing pseudocode
Problem: Find the longest word in the sentence
1. Read sentence
2. Validate input
3. Init longestWordLength as 0
4. Check that the sentence has a word to process read word
from the sentence as currentWord
5. Check currentWordLength is greater than
longestWordLength, if yes, then record currentWord as
longestWord and its length in longestWordLength
6. Repeat step 3 to 5 until sentence has words to process
7. Return longestWord

7. Step 5
Trace the solution with the test cases/dry run - define
the test cases
Test Input Expected Output
Invalid input Do not provide input,
Press enter
Sentence is not provided.
Provide single word Hello The longest word is: Hello
Provide sentence with
single longest word
Satyamev Jayate
Provide sentence with
multiple longest word
The first longest word will
be provided
Hi Ajay , Hi Uday
The longest word is: Satyamev
The longest word is: Ajay
Test sentence provided
in problem statement
The cat sat on the mat
with another cat
The longest word is: another
Problem: Find the longest word in the sentence

8. Step 6
Writing code
Problem:
Find the
longest
word in the
sentence
/*
1. Read sentence
2. Validate input
3. Take longestWordLength as 0
4. Check sentence has word to process
Read word from sentence as currentWord
5. Check currentWord length is greater than longestWordLength
If yes, then record currentWord as longestWord and its length in longestWordLength
6. Repeat step 3 to 5 untill sentence has words to process
7. Return longestWord
*/
#include <stdio.h>
#include <string.h>
/*
Return next word from sentence
Input:
inputSentence: Input sentence to read word
wordStartPos: Start position of next word
word: Function keep word in it.
Return: nextWordStartPos
*/
int getWord(char* inputSentence, int wordStartPos, char* currWord)
{
int nextWordStartPos = 0;
int i = 0;
int j = 0;
// Start reading word from wordStartPos
for (i = wordStartPos; i <= strlen(inputSentence); i++)
{
// Skip the space, new line and end of line characters
if (inputSentence[i] != ' ' && inputSentence[i] != 'n' && inputSentence[i] != '0')
{
// Record current word
currWord[j++] = inputSentence[i];

9. Step 6
Writing code
Problem:
Find the
longest
word in the
sentence
}
else
{
// Found space, new line or end of line characters
// Finished reading word
// Terminate word by adding 0
currWord[j] = '0';
// Record current position of inputSentence as nextWordStartPos, we will use it in next pass
nextWordStartPos = i + 1;
// Skip rest of the sentence as we finished with reading word
break;
}
}
return nextWordStartPos;
}
/*
Check sentence has more words to process
Input:
inputSentence: Input sentence to read word
nextWordStartPos: Position in inputSentence untill we prcossed
Return:
hasMoreWords: 0 If we processed all words in sentence
hasMoreWords: 1 If word is available to process
*/
int hasMoreWords(char* inputSentence, int nextWordStartPos)
{
int hasMoreWords = 1;
if((nextWordStartPos >= strlen(inputSentence)) || inputSentence[nextWordStartPos] == '0')
{
// We reached end of sentence
// No more words to process
hasMoreWords = 0;
}
return hasMoreWords;
}

10. Step 6
Writing code
Problem:
Find the
longest
word in the
sentence
/*
Return longest word from sentence
Input:
inputSentence: Input sentence to read word
longestWord: Keep longest word in it.
*/
void getLongestWord(char* inputSentence, char* longestWord)
{
char currWord[64];
int i = 0;
int j = 0;
int currLongestWordLen = 0;
int nextWordStartPos = 0;
while(hasMoreWords(inputSentence, nextWordStartPos) == 1)
{
// Sentence has words which are still not processed
// Get next word from sentence
// Record next word start position which will be rquired in next pass
nextWordStartPos = getWord(inputSentence, nextWordStartPos, currWord);
if (strlen(currWord) > currLongestWordLen)
{
// Current word lenth is rater than current longest word, so we have new longest word record
it
strcpy(longestWord, currWord);
// Record length of new lonest word
currLongestWordLen = strlen(longestWord);
}
}
}
/*
Validate program input
Input:
inputSentence: Input sentence to read word

11. Step 6
Writing code
Problem:
Find the
longest
word in the
sentence
Return:
isValid: 0 If input is valid
isValid: 1 I input is not valid
*/
int validateInput(char* inputSentence)
{
int isValid = 1;
// Check input string is provided
// we are comparing the length to be greater then 1 as fgets puts the enter/return as well in the input while accepting
the input.
if(strlen(inputSentence) > 1)
{
isValid = 0;
}
return isValid;
}
}
int main()
{
// Boundaries
// Handling the sentence of max legnth 512
// Handling longest word of upto legnth 64
char inputSentence[512], longestWord[64];
// Read input sentence from command line
printf("Enter a string:n");
fgets(inputSentence, sizeof(inputSentence), stdin);
if(validateInput(inputSentence) == 1)
{
// Input is invalid
printf("Sentence is not provided.n");
return 1;
}

12. Step 6
Writing code
Problem:
Find the
longest
word in the
sentence
// Find Longest word in sentence
// The longest word will be returned in parameter longestWord
getLongestWord(inputSentence, longestWord);
printf("The longest word is: ");
puts(longestWord);
return 0;
}

13. Problem: Find the longest word in the sentence
Test Input Expected Output
Invalid input Do not provide input,
Press enter
Sentence is not provided.
Provide single word Hello The longest word is: Hello
Provide sentence with
single longest word
Satyamev Jayate
Provide sentence with
multiple longest word
The first longest word will
be provided
Hi Ajay , Hi Uday
The longest word is: Satyamev
The longest word is: Ajay
Test sentence provided
in problem statement
The cat sat on the mat
with another cat
The longest word is: another
Step 7 Evaluate - Dry run