C++ do() while control execution statement
The do() while is another control execution statement in C++.Unlike the ‘if() else’ statement whose decision making is based on each of the expression provided to ‘if() or else if()’ statement the ‘do() while’ statement can iterate a code or program until certain condition is fulfilled.The rule of ‘do() while’ is straightforward,if the expression under ‘while()’ statement returns false the code under do statement stops executing.
Link :C++ while statement
A pictorial representation is given below.
The syntax of ‘do() while’statement is given below.
do() { //code1 :the code to be executed } while( expression1 ); //do not forget ';' after the closing bracket
As long as the expression ‘expression1’ returns true or 1 the code1 will keep on executing.Here is simple code example.
int i=0 ; do { cout<< i << endl ; ++i; //i value keeps on increasing } while( i<3 );
The output is,
0
1
2
What the above code does is simple,the value of ‘i’ is printed out as long as ‘i’ is smaller than 3.The ‘++’ operator in ‘++i’ is known as increment operator and it’s function is to increase the variable value by 1 and in this case ‘i’.
Another code example is given below.It find the sum of the first 10 natural number.
int i=1 , sum=0 ; do { sum=i+sum; ++i; } while( i<11); cout<<"The sum of first " << --i << " natural number is:" << sum ;
Output,
The sum of first 10 natural number is:55
Note the ‘do() while’ statement is similar to ‘while()’ statement,in fact most of the time ‘while()’ is used instead of ‘do() while’ statement.