Skip to main content

Do-While Loop inc C Programming (syntax and Example)

DO..WHILE - DO..WHILE loops are useful for things that want to loop at least once.

The structure is
 
do 
 } while ( condition );

Notice that the condition is tested at the end of the block instead of the beginning, so the block will be executed at least once. If the condition is true, we jump back to the beginning of the block and execute it again. A do..while loop is almost the same as a while loop except that the loop body is guaranteed to execute at least once. A while loop says "Loop while the condition is true, and execute this block of code", a do..while loop says "Execute this block of code, and then continue to loop while the condition is true".

Example:
#include <stdio.h>

int main()
{
  int x;

  x = 0;
  do 
  {
    /* "Hello, world!" is printed at least one time
      even though the condition is false */
      printf( "Hello, world!\n" );
  } while ( x != 0 );
  getchar();
} 
Keep in mind that you must include a trailing semi-colon after the while in the above example. A common error is to forget that a do..while loop must be terminated with a semicolon (the other loops should not be terminated with a semicolon, adding to the confusion). Notice that this loop will execute once, because it automatically executes before checking the condition. 

Comments

Popular posts from this blog

CIVIL SERVICES' (I.A.S.) EXAMINATION

The Union Public Service Commission (U.P.S.C.)  conducts Civil Services' Examination once a year in two stages. The Preliminary Examination (Objective Type) for selection of candidates for the Main Examination is held in the month of May. The Civil Services Main Examination  is held in the months of October/November. Blank application forms and other particulars are published in the Employment News, generally in the month of December. The last date for the submission of applications to the Secretary, Union Public Service Commission, Dholpur House, Shahjahan Road, NewDelhi-11001 1 is usually the last week of January of the year of examination. The Combined Civil Services Examination is conducted for Recruitment to the following Services/Posts: 1. Indian Administrative Service. 2. Indian Foreign Service. 3. Indian Police Service. 4. Indian P & T Accounts & Finance Service, Group 'A'. 5. Indian Audit and Accounts Service, Group 'A'. 6. Indian Customs and Centr

Predict the output or error(s) for the following:

1 . void main(){ int const * p=5; printf("%d",++(*p)); } Answer: Compiler error: Cannot modify a constant value. Explanation: p is a pointer to a "constant integer". But we tried tochange the value of the "constant integer". 2. main() {  char s[ ]="man"; int i;  for(i=0;s[ i ];i++) printf("\n%c%c%c%c",s[i],*(s+i),*(i+s),i[s]); } Answer: mmmm aaaa nnnn Explanation: s[i], *(i+s), *(s+i), i[s] are all different ways of expressing the same idea. Generally array name is the base address for that array. Here s is the base address. i is the index number/displacement from the base address. So, indirecting it with * is same as s[i]. i[s] may be surprising. But in the case of C it is same as s[i]. 3 . main(){  float me = 1.1;  double you = 1.1;  if(me==you) printf("I love U"); else printf("I hate U"); } Answer: I hate U Explanation : For floating point numbers (float, double, long double)

AGRICULTURAL SCIENTIST RECRUITMENT BOARD

Agricultural Research Service National   Eligibility  Test/ Senior Research Fellowship Examination  The Agricultural Scientists Recruitment Board (ASRB)  holds a Competitive Examination for recruiting Scientists of the ARS in the pay scale of Rs. 8,000-13,500 in the ICAR Institutes, combined with National Eligibility Test (NET) for recruitment of Lecturers and Assistant Professors by the State Agricultural Universities (SAUS) and for award of ICAR Senior Research Fellowships. The selected candidates for Agricultural Research Service must serve in the institutes to which they are posted until they find appointment for higher positions through selection at other institutes. (i) Candidates successful in ARS are appointed as Scientists in the Indian Council of Agricultural Research in the pay scale of Rs. 8,000-13,500. (ii) Candidates clearing the National Eligibility Test are recommended to various State Agricultural Universities who will consider them for appointment as Lecturers or A