C、C++、 Javawhile 和 do-while 循环的区别

while循环：

while 循环是一种控制流语句，它允许根据给定的布尔条件重复执行代码。 while 循环可以被认为是一个重复的 if 语句。
句法 ：

while (boolean condition)
{
   loop statements...
}

流程图：

例子：

C

#include 
  
int main()
{
  
    int i = 5;
  
    while (i < 10) {
        printf("GFG\n");
        i++;
    }
  
    return 0;
}

C++

#include 
using namespace std;
  
int main()
{
  
    int i = 5;
  
    while (i < 10) {
        i++;
        cout << "GFG\n";
    }
  
    return 0;
}

Java

import java.io.*;
  
class GFG {
    public static void main(String[] args)
    {
  
        int i = 5;
  
        while (i < 10) {
            i++;
            System.out.println("GfG");
        }
    }
}

输出：

GFG
GFG
GFG
GFG
GFG

do-while 循环：

do while 循环类似于while 循环，唯一的区别是它在执行语句后检查条件，因此是退出控制循环的一个示例。

句法：

do
{
    statements..
}
while (condition);

流程图：

例子：

C

#include 
  
int main()
{
  
    int i = 5;
  
    do {
        printf("GFG\n");
        i++;
    } while (i < 10);
  
    return 0;
}

C++

#include 
using namespace std;
  
int main()
{
  
    int i = 5;
  
    do {
        i++;
        cout << "GFG\n";
    } while (i < 10);
  
    return 0;
}

Java

import java.io.*;
  
class GFG {
    public static void main(String[] args)
    {
  
        int i = 5;
  
        do {
            i++;
            System.out.println("GfG");
        } while (i < 10);
    }
}

输出：

GFG
GFG
GFG
GFG
GFG

这是差异表：

while	do-while
Condition is checked first then statement(s) is executed.	Statement(s) is executed atleast once, thereafter condition is checked.
It might occur statement(s) is executed zero times, If condition is false.	At least once the statement(s) is executed.
No semicolon at the end of while. while(condition)	Semicolon at the end of while. while(condition);
If there is a single statement, brackets are not required.	Brackets are always required.
Variable in condition is initialized before the execution of loop.	variable may be initialized before or within the loop.
while loop is entry controlled loop.	do-while loop is exit controlled loop.
while(condition) { statement(s); }	do { statement(s); } while(condition);

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