Detailed explanation of loop statements in C++

C is an efficient programming language with powerful features and a wide range of applications. Loop statements are one of the most important parts of C. C provides several loop statements to make it easier for programmers to iterate data. This article will introduce the loop statement in C in detail.

1. for loop

The for loop is an iterative statement that allows programmers to easily perform a specified operation repeatedly. The basic syntax of a for loop is as follows:

for(initialization; condition; increment)
{
    // code to be executed
}

Among them, initialization is the initialization expression, which is executed once before the start of the loop; condition is the loop condition expression, if it is true, the loop continues to be executed; increment is the increment A quantitative expression that is executed once at the end of each loop.

For example, the following code snippet will print numbers from 0 to 9:

for(int i=0; i<10; i++)
{
    cout<<i<<endl;
}

At this time, the program will output the numbers 0 to 9 on the console.

2. While loop

The while loop is a common iteration structure that is used to repeatedly execute one or more statements until the condition is no longer true. The basic syntax of the while loop is as follows:

while(condition)
{
    // code to be executed
}

The condition is calculated. If the result is true, the loop body will be executed; otherwise, the program will jump out of the loop and continue executing the program after the loop.

The following code segment prints the numbers 1~5:

int i = 1;
while(i <= 5)
{
    cout << i << endl;
    i++;
}

At this time, the program will output the numbers 1~5 on the console.

3. do-while loop

The do-while loop is similar to the while loop, but the do-while loop will test the loop condition at least once after executing the loop body. The basic syntax is as follows:

do
{
   // code to be executed
} while(condition);

At the beginning of the loop, first execute the statements in the loop body, and then calculate the condition. If the result is true, execute the code in the loop body. When the condition is false, break out of the loop.

The output result of the following code is consistent with the previous while loop:

int i = 1;
do
{
    cout << i << endl;
    i++;
} while (i <= 5);

4. Nested loops

Nested loops refer to nested loops within a loop. Another cycle. Use nested loops to handle complex logic operations.

The following code snippet demonstrates how to use nested loops to output the multiplication table:

for (int i = 1; i <= 9; i++)
{
    for (int j = 1; j <= i; j++)
    {
        cout << j << "*" << i << "=" << i * j << "    ";
    }
    cout << endl;
}

The above code will output the following multiplication table:

1*1=1    
1*2=2    2*2=4    
1*3=3    2*3=6    3*3=9    
1*4=4    2*4=8    3*4=12    4*4=16    
1*5=5    2*5=10    3*5=15    4*5=20    5*5=25    
1*6=6    2*6=12    3*6=18    4*6=24    5*6=30    6*6=36    
1*7=7    2*7=14    3*7=21    4*7=28    5*7=35    6*7=42    7*7=49    
1*8=8    2*8=16    3*8=24    4*8=32    5*8=40    6*8=48    7*8=56    8*8=64    
1*9=9    2*9=18    3*9=27    4*9=36    5*9=45    6*9=54    7*9=63    8*9=72    9*9=81

Summary:

This article mainly introduces three common loop statements: for loop, while loop and do-while loop, as well as the use of nested loops. Programmers can choose different loop statements to complete specific tasks according to the actual situation, improving the efficiency and readability of the program.

The above is the detailed content of Detailed explanation of loop statements in C++. For more information, please follow other related articles on the PHP Chinese website!