C Syntax

The do statement provides an iterative structure to condidionally repeat execution of a section of code sy least once.

The do statement is used as an iteration, or looping, structure.  Loop control occurs after the body of the loop. The body of the loop will be executed one or more times.

Syntax Diagrams

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BNF

do-statement

::= 'do' <statement> 'while' '(' <expression> ')' ';'

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EBNF

do-statement

::= 'do' <statement> 'while' '(' <expression> ')' ';'

do-statement

The do-while statement provides iteration, or looping, control.

The body of a do-while is always executed at least once.

The expression is evaluated after the statement has been executed.

If the expression evaluates to true, the process is repeated.

If the expression evaluates to false, execution continues with the next statement after the if statement.

expression

A boolean false, an arithmetic 0, or a null pointer are all interpreted as false.

A boolean true, an arithmetic expression not equal to 0, or a non-null pointer are all interpreted as true.

• The statement part is usually a compound statement, that is, a statement list enclosed in braces.
• The do statement is also referred to as the do-while statement.

#include <stdio.h>

int main () {
  unsigned i;

  i = 0;
  do {
    if (i % 2 == 1) {
      printf ("%u is an odd number\n", i);
    }
    ++i;
  } while (i < 10);
  
  return 0;
}

1 is an odd number
3 is an odd number
5 is an odd number
7 is an odd number
9 is an odd number