For Loop in Programming Language

For Loop

The for loop is one of the most commonly used loops in programming. It is typically used when the number of iterations is known beforehand. The syntax generally includes an initialization, a condition, and an increment/decrement operation.

Flowchart

Which loop to use? For or While

Language: Java

<span class="pln">
</span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">class</span><span class="pln"> </span><span class="typ">Main</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
    </span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">static</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> main</span><span class="pun">(</span><span class="typ">String</span><span class="pun">[]</span><span class="pln"> args</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
        </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">int</span><span class="pln"> i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class="pun">;</span><span class="pln"> i </span><span class="pun">&lt;</span><span class="pln"> </span><span class="lit">5</span><span class="pun">;</span><span class="pln"> i</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
            </span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Iteration: "</span><span class="pln"> </span><span class="pun">+</span><span class="pln"> i</span><span class="pun">);</span><span class="pln">
        </span><span class="pun">}</span><span class="pln">
    </span><span class="pun">}</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span>

Language: Python

<span class="pln">
</span><span class="kwd">for</span><span class="pln"> i </span><span class="kwd">in</span><span class="pln"> range</span><span class="pun">(</span><span class="lit">5</span><span class="pun">):</span><span class="pln">
    </span><span class="kwd">print</span><span class="pun">(</span><span class="str">"Iteration:"</span><span class="pun">,</span><span class="pln"> i</span><span class="pun">)</span><span class="pln">
</span>

Language: C++

<span class="pln">
</span><span class="com">#include</span><span class="pln"> </span><span class="str">&lt;iostream&gt;</span><span class="pln">
</span><span class="kwd">using</span><span class="pln"> </span><span class="kwd">namespace</span><span class="pln"> std</span><span class="pun">;</span><span class="pln">

</span><span class="kwd">int</span><span class="pln"> main</span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
    </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">int</span><span class="pln"> i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class="pun">;</span><span class="pln"> i </span><span class="pun">&lt;</span><span class="pln"> </span><span class="lit">5</span><span class="pun">;</span><span class="pln"> i</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
        cout </span><span class="pun">&lt;&lt;</span><span class="pln"> </span><span class="str">"Iteration: "</span><span class="pln"> </span><span class="pun">&lt;&lt;</span><span class="pln"> i </span><span class="pun">&lt;&lt;</span><span class="pln"> endl</span><span class="pun">;</span><span class="pln">
    </span><span class="pun">}</span><span class="pln">
    </span><span class="kwd">return</span><span class="pln"> </span><span class="lit">0</span><span class="pun">;</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span>

Language: C#

<span class="pln">
</span><span class="kwd">using</span><span class="pln"> </span><span class="typ">System</span><span class="pun">;</span><span class="pln">

</span><span class="kwd">class</span><span class="pln"> </span><span class="typ">Program</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
    </span><span class="kwd">static</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> </span><span class="typ">Main</span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
        </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">int</span><span class="pln"> i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class="pun">;</span><span class="pln"> i </span><span class="pun">&lt;</span><span class="pln"> </span><span class="lit">5</span><span class="pun">;</span><span class="pln"> i</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
            </span><span class="typ">Console</span><span class="pun">.</span><span class="typ">WriteLine</span><span class="pun">(</span><span class="str">"Iteration: "</span><span class="pln"> </span><span class="pun">+</span><span class="pln"> i</span><span class="pun">);</span><span class="pln">
        </span><span class="pun">}</span><span class="pln">
    </span><span class="pun">}</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span>

Language: JavaScript

<span class="pln">
</span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">let</span><span class="pln"> i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class="pun">;</span><span class="pln"> i </span><span class="pun">&lt;</span><span class="pln"> </span><span class="lit">5</span><span class="pun">;</span><span class="pln"> i</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
    console</span><span class="pun">.</span><span class="pln">log</span><span class="pun">(</span><span class="str">"Iteration: "</span><span class="pln"> </span><span class="pun">+</span><span class="pln"> i</span><span class="pun">);</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span>

Language: PHP

<span class="pln">
</span><span class="pun">&lt;?</span><span class="pln">php
</span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="pln">$i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class="pun">;</span><span class="pln"> $i </span><span class="pun">&lt;</span><span class="pln"> </span><span class="lit">5</span><span class="pun">;</span><span class="pln"> $i</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
    echo </span><span class="str">"Iteration: "</span><span class="pln"> </span><span class="pun">.</span><span class="pln"> $i </span><span class="pun">.</span><span class="pln"> </span><span class="str">"&lt;br&gt;"</span><span class="pun">;</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span><span class="pun">?&gt;</span><span class="pln">
</span>

Language: Swift

<span class="pln">
</span><span class="kwd">for</span><span class="pln"> i </span><span class="kwd">in</span><span class="pln"> </span><span class="lit">0.</span><span class="pun">.&lt;</span><span class="lit">5</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
    </span><span class="kwd">print</span><span class="pun">(</span><span class="str">"Iteration: \(i)"</span><span class="pun">)</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span>

Language: Go

<span class="pln">
</span><span class="kwd">package</span><span class="pln"> main
</span><span class="kwd">import</span><span class="pln"> </span><span class="str">"fmt"</span><span class="pln">

func main</span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
    </span><span class="kwd">for</span><span class="pln"> i </span><span class="pun">:=</span><span class="pln"> </span><span class="lit">0</span><span class="pun">;</span><span class="pln"> i </span><span class="pun">&lt;</span><span class="pln"> </span><span class="lit">5</span><span class="pun">;</span><span class="pln"> i</span><span class="pun">++</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
        fmt</span><span class="pun">.</span><span class="typ">Println</span><span class="pun">(</span><span class="str">"Iteration:"</span><span class="pun">,</span><span class="pln"> i</span><span class="pun">)</span><span class="pln">
    </span><span class="pun">}</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span>

Language: Ruby

<span class="pln">
</span><span class="kwd">for</span><span class="pln"> i </span><span class="kwd">in</span><span class="pln"> </span><span class="lit">0.</span><span class="pun">..</span><span class="lit">4</span><span class="pln">
  puts </span><span class="str">"Iteration: #{i}"</span><span class="pln">
</span><span class="kwd">end</span><span class="pln">
</span>

Language: Kotlin

<span class="pln">
fun main</span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
    </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="pln">i </span><span class="kwd">in</span><span class="pln"> </span><span class="lit">0.</span><span class="pun">.</span><span class="lit">4</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
        println</span><span class="pun">(</span><span class="str">"Iteration: $i"</span><span class="pun">)</span><span class="pln">
    </span><span class="pun">}</span><span class="pln">
</span><span class="pun">}</span><span class="pln">

</span>

Language: X++

<span class="pln">
</span><span class="kwd">static</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> </span><span class="typ">ForLoopExample</span><span class="pun">(</span><span class="typ">Args</span><span class="pln"> _args</span><span class="pun">)</span><span class="pln">
</span><span class="pun">{</span><span class="pln">
    </span><span class="kwd">int</span><span class="pln"> i</span><span class="pun">;</span><span class="pln">
    
    </span><span class="com">// For loop that runs 5 times</span><span class="pln">
    </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="pln">i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">1</span><span class="pun">;</span><span class="pln"> i </span><span class="pun">&lt;=</span><span class="pln"> </span><span class="lit">5</span><span class="pun">;</span><span class="pln"> i</span><span class="pun">++)</span><span class="pln">
    </span><span class="pun">{</span><span class="pln">
        info</span><span class="pun">(</span><span class="pln">strFmt</span><span class="pun">(</span><span class="str">"Iteration: %1"</span><span class="pun">,</span><span class="pln"> i</span><span class="pun">));</span><span class="pln">
    </span><span class="pun">}</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span>