C++ program to remove spaces from a string using String stream

As the given problem says, we need to remove spaces from the string using a string stream. As the name suggests, a string stream converts a string into a stream. It works similar to cin in C++. It associates a string object that can access the string buffer in which it is stored.

string s =" a for apple, b for ball";
res = solve(s);

With a string buffer, we will read each word one by one and then concatenate it into a new string which will be our answer.

Note ? The class string stream is available in the sstream header file in c++, so we need to include it.

Let us look at some input/output scenarios

Assume the input taken by the function has no spaces in it, the output result achieved would be the same as the input ?

Input: "Tutorialspoint"
Result: "Tutorialspoint"

Assume the input taken by the function has no spaces in it, the output result achieved would be the string void of all the spaces in it ?

Input: "Tutorials Point"
Result: "TutorialsPoint"

Assume the input taken by the function has only spaces in it, the method fails to provide an output result ?

Input: " "
Result: 

Algorithm

• Consider an input string with characters.

• The string is checked to not be empty and using stringstream keyword all the spaces present in the input are removed.

• This process is done until the stringstream pointer reaches the end of line.

• If it reaches end of line in the string, the program terminates.

• The updated string is returned to the output result.

Example

For example, we have a string such as "a for apple, b for a ball," we need to convert that to "aforapple,bforball."

Following a detailed code of removing the spaces from string inputs to make it a stream of characters ?

<div class="execute"></div><div class="code-mirror  language-cpp" contenteditable="plaintext-only" spellcheck="false" style="outline: none; overflow-wrap: break-word; overflow-y: auto; white-space: pre-wrap;"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span> <span class="token string"><iostream></span></span>
<span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span> <span class="token string"><sstream></span></span>
<span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span>
string <span class="token function">solve</span><span class="token punctuation">(</span>string s<span class="token punctuation">)</span> <span class="token punctuation">{</span>
   string answer <span class="token operator">=</span> <span class="token string">""</span><span class="token punctuation">,</span> temp<span class="token punctuation">;</span>
   stringstream ss<span class="token punctuation">;</span>
   ss <span class="token operator"><<</span> s<span class="token punctuation">;</span>
   <span class="token keyword">while</span><span class="token punctuation">(</span><span class="token operator">!</span>ss<span class="token punctuation">.</span><span class="token function">eof</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      ss <span class="token operator">>></span> temp<span class="token punctuation">;</span>
      answer<span class="token operator">+=</span>temp<span class="token punctuation">;</span>
   <span class="token punctuation">}</span>
   <span class="token keyword">return</span> answer<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">int</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
   string s <span class="token operator">=</span><span class="token string">"a for apple, b for ball"</span><span class="token punctuation">;</span>
   cout <span class="token operator"><<</span> <span class="token function">solve</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">;</span>
   <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
</div><div class="output-wrapper"><div class="console-close"></div><div class="code-output"></div></div>

Output

Aforapple,bforball

Example (Using getline)

We also have another approach using getline to solve the same query in C++.

<div class="execute"></div><div class="code-mirror  language-cpp" contenteditable="plaintext-only" spellcheck="false" style="outline: none; overflow-wrap: break-word; overflow-y: auto; white-space: pre-wrap;"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span> <span class="token string"><iostream></span></span>
<span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span> <span class="token string"><sstream></span></span>
<span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span>
string <span class="token function">solve</span><span class="token punctuation">(</span>string s<span class="token punctuation">)</span> <span class="token punctuation">{</span>
   stringstream <span class="token function">ss</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">;</span>
   string temp<span class="token punctuation">;</span>
   s <span class="token operator">=</span> <span class="token string">""</span><span class="token punctuation">;</span>
   <span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token function">getline</span><span class="token punctuation">(</span>ss<span class="token punctuation">,</span> temp<span class="token punctuation">,</span> <span class="token string">' '</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      s <span class="token operator">=</span> s <span class="token operator">+</span> temp<span class="token punctuation">;</span>
   <span class="token punctuation">}</span>
   <span class="token keyword">return</span> s<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">int</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
   string s <span class="token operator">=</span><span class="token string">"a for apple, b for ball"</span><span class="token punctuation">;</span>
   cout <span class="token operator"><<</span> <span class="token function">solve</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">;</span>
   <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
</div><div class="output-wrapper"><div class="console-close"></div><div class="code-output"></div></div>

Output

Aforapple,bforball

Conclusion

We see that using string stream, the string is stored in the buffer, and we can get the string word by word and concatenate it, removing spaces.