At what condition do we use do while loop ?

Answer 1

Do while loops are used to execute the instructions at least once. For example if I want to get the input of a number and accept it if it is grater than 0, I should write
//this is C language
int i;
do{
scanf("%d",&i);
}while(i<=0);
So if "i" is less than 0 (or equal), the user will have to input the number again because the exit-condition would be true.

Answer 2

thanks

Answer 3

so if you are writing a program how do we know which loop to be used

Answer 4

As I said above you should use it if you are sure that the instructions will be executed at least once.
There is not a precise rule, the various cases come out after you do exercises.
My example is one common situation where you use it to accept a number if it satisfies some conditions, but most of the other things (not everything) can be done with all the types of loops.

Answer 5

You're welcome