Talking about the for loop and foreach loop in C,

Talking about the for loop and foreach loop in C,

In fact, the for loop and the foreach loop can be considered as subordinate, that is, the foreach loop can be converted into a for loop, but the for loop may not be converted into a foreach loop.

The following describes two types of loops:

1. for Loop

Code Format:

For (expression 1; loop condition; expression 2)

{

Loop body

}

Code Description:

First, run expression 1;

Then judge whether the condition is true. If it is true, execute the loop body and then run expression 2;

Then judge the cyclic condition ...... The loop ends only when the cyclic condition is false.

Note:

Expression 1: Any code can be executed only once;

Expression 2: Any code can be executed after the loop body is executed.

2. foreach Loop

Code Format:

Foreach (in array or set of data type variables)
{
Loop body

}

Code Description:

Extract the data of each item from an array or set in sequence, and assign the data to the loop variable. After each value is assigned, the loop body runs once.

Note:

Foreach loops can only be used to traverse arrays and collections;

A foreach loop is also called a read-only loop. in the loop body, the set or array cannot be changed;

The data type must be the same as the data type of each item in an array or set.

 

However, what are the differences and advantages between a foreach loop and a for loop? The following is a brief summary:

Foreach loop for Loop

Can only be used for traversal; can be used for any form of repeated behavior;

You cannot change the cycle target. You can perform any operations in the loop body;

Fast traversal and high execution efficiency. The traversal speed is slow and the execution efficiency is low.

Conclusion: If you want to traverse a set or array, and you only need to read but not change it during the traversal process, it is most appropriate to use a foreach loop. Otherwise, select another loop as needed.

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