What is the usage of the do-while statement in the C language?

The do-while statement is a type of loop statement in the C language that executes a block of statements and then decides whether to continue the loop based on whether a condition is met.

The basic syntax of the do-while statement is as follows:

do {
    // 循环体语句块
} while (条件表达式);

The process is carried out as follows:

1. First, execute the statements within the loop body.
2. Next, evaluate the value of the conditional expression.
3. If the condition expression is true (non-zero), continue executing the statements in the loop body and then repeat step 2.
4. If the value of the conditional expression is false (zero), then exit the loop and continue executing the code following the loop.

One characteristic of the do-while statement is that regardless of whether the condition is met, the statements within the loop will be executed at least once. Thus, even if the condition is not initially met, the statements within the loop will still be executed once.

The do-while statement is used in cases where the loop body needs to be executed at least once and when the number of iterations is not predetermined.