133 lines
2.2 KiB
Markdown
133 lines
2.2 KiB
Markdown
---
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title: For Loop
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---
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# For Loop
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The for loop executes a block of code repeatedly until a specified conditional expression evaluates to false.
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Anatomy of for loop:
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```
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for (initialization; condition; iterator)
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{
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body
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}
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```
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- initialization - The initialization statement(s) sets the initial condition and run only once before you enter the body of the loop.
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- condition - Boolean expression which determines whether the body of the loop should execute again or the loop should exit.
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- iterator - Executes after each iteration of the body of the loop.
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### Example 1
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```
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for (int i = 0; i < 5; i++)
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{
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Console.WriteLine("Number " + i);
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}
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```
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### Output:
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```
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> Number 0
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> Number 1
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> Number 2
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> Number 3
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> Number 4
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```
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### Example 2
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```
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int j = 0;
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for (int i = 0; j < 5; i++)
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{
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Console.WriteLine("Numbers {0} {1}", i, j);
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j++;
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}
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```
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### Output:
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```
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> Numbers 0 0
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> Numbers 1 1
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> Numbers 2 2
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> Numbers 3 3
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> Numbers 4 4
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```
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### Example 3 - Simplification of Example 2
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```
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for (int i = 0, j = 0; i < 5 && j < 5; i++, j++)
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{
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Console.WriteLine("Numbers {0} {1}", i, j);
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}
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```
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### Output:
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```
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> Numbers 0 0
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> Numbers 1 1
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> Numbers 2 2
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> Numbers 3 3
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> Numbers 4 4
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```
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### Example 4
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```
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for (int i = 5; i > 0; i--)
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{
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Console.WriteLine("Number " + i);
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}
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```
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### Output:
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```
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> Number 5
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> Number 4
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> Number 3
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> Number 2
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> Number 1
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```
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### Example 5
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```
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// Infinite loop - The loop body is executed infinitely
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for (; ;)
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{
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Console.WriteLine("The universe is infinite");
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}
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// Anything after infinite loop is reported as "Unreachable code detected" in Visual Studio
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Console.WriteLine("Never considered for execution");
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```
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### Output:
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```
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> The universe is infinite
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> The universe is infinite
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> The universe is infinite
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> ....
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> ....
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```
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### Example 6
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```
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int i = 0;
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for (; i < 5;)
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{
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Console.WriteLine("Number " + i);
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i++;
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}
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```
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### Output:
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```
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> Number 0
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> Number 1
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> Number 2
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> Number 3
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> Number 4
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```
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### Other Resources
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- [Microsoft Documentation](https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/for)
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## End
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