➤ If-else Statement in C
➤ Programs on if-else
➤ Switch Case in C
➤ Switch case Programs
➤ Conditional Operator
➤ While loop in C
➤ Do-while loop in C
➤ While vs do-while
➤ For loop in C
➤ Break keyword in C
➤ Continue keyword in C
➤ Break vs Exit in C
➤ Goto keyword in C
☕️ Flow Control Programs
➤ Largest in 3 Numbers
➤ Find Grade of student
➤ Find the absolute value
➤ Vowel or Consonant
➤ Leap Year Program
➤ Simple calculator in C
➤ Check Odd or Even
➤ Roots of Quadratic Equation
➤ Find Reverse of Number
➤ Factors of a number in C
➤ Generate Multiplication table
➤ Find Power of a Number
➤ Find GCD and LCM
➤ Find factorial of Number
➤ Count Number of Digits
➤ Sum of digits in Number
➤ Sum of N Natural Numbers
➤ Sum of Squares of Natural No.
➤ Find Sum of Odd Numbers
➤ Find the Sum of Series
➤ Find Fibonacci series in C
➤ Sum of the Fibonacci series
➤ Sum until enters +ve numbers
➤ Sum of max 10 no. & Skip -ve
☕️ C Conversion Programs
➤ Celsius to Fahrenheit
➤ Fahrenheit to Celsius
➤ Decimal ↔ Binary
➤ Decimal ↔ Octal
➤ Octal ↔ Binary in C
☕️ Number Programs in C
➤ Prime Number in C
➤ Strong Number in C
➤ Krishnamurthy Number
➤ Neon Number in C
➤ Palindrome number
➤ Perfect Number in C
➤ Armstrong Number
☕️ Pattern Programs in C
➤ Pattern programs in C
➤ Printing pattern using loops
➤ Floyd’s triangle Program
➤ Pascal Triangle Program
➤ Pyramid Star Pattern in C
➤ Diamond Pattern Programs
➤ Half Diamond pattern in C
➤ Print Diamond Pattern
➤ Hollow Diamond Pattern
➤ Diamond Pattern of Numbers
Previously you have learned about while loop and do while loop in C. Now, we will see the basic difference between while and do while with example.
Difference1:
The while loop is a pre-test loop but do-while is a post-test loop.
The while loop is pre-test loop, where firstly the condition is checked and if the condition is true then only the statements of the while loop execute. The do-while loop is a post-test loop. In the do-while loop, the statements of the do-while loop are executed after that, the condition is evaluated, and if the condition is true then again the statements of the do-while loop are executed.
Differences in the syntax of while and do-while loop
Difference2: They have different syntaxes.
Syntax of while loop
while (condition)
{
// statements
}Syntax of the do-while loop
do
{
// statements
} while(condition);Difference3: The do-while should be terminated semicolon but while loop can’t.
While loop can’t be terminated with a semicolon but the do-while loop should be terminated with a semicolon.
Difference4:
The condition of the while loop is at the top of the loop but the condition of the do-while loop is at the bottom of the loop.
Difference5: They have different flowcharts.
Flowchart for while loop
Flowchart for do-while loop
Execution of while loop and do-while loop
Difference4: The while loop can execute 0 to N times, but the do-while loop executes 1 to N times.
The statements of the do-while loop execute at least 1 time in every condition. In the while loop, the test expression evaluates false in first checking then the statements of the while loop is not executed. But the condition of the do-while loop is checked at the end of the loop, so it is guaranteed that the statements of the do-while loop execute at least once.
//while loop
#include<stdio.h>
int main()
{
int i=1;
while (i<1)
{
printf("Hello\n");
i++;
}
printf("Loop completed");
return 0;
}Output:-
Loop completed
// do-while loop
#include<stdio.h>
int main()
{
int i=1;
do
{
printf("Hello\n");
i++;
} while(i<1);
printf("Loop completed");
return 0;
}Output:-
Hello
Loop completed
The statements of while loop will execute or not it depend on the condition of the while loop. If the condition of the while loop is true then the statements of the while execute, and it will execute until the condition becomes false.
The statements of the do-while loop execute one time then it checks the condition. So, the first time execution of the do-while loop statements doesn’t depend upon the condition of the do-while loop. After executing one time the statements of the do-while loop, the condition is checked. If the condition is true then statements of the do-while loop execute again until the condition becomes false.
Sample program of while and do-while loop
C Program to Print Even Numbers using while loop
#include<stdio.h>
int main()
{
int m,n;
printf("Enter range: ");
scanf("%d %d",&m, &n);
while (m<=n)
{
if(m%2==0) printf("%d ",m);
++m;
}
return 0;
}Output:-
Enter range: 5 15 6 8 10 12 14
C Program to Print Even Numbers using the do-while loop
#include<stdio.h>
int main()
{
int m,n;
printf("Enter range: ");
scanf("%d %d",&m, &n);
do
{
if(m%2==0) printf("%d ",m);
++m;
} while(m<=n);
return 0;
}Output:-
Enter range: 10 20 10 12 14 16 18 20
C Program to Print Odd Numbers using while loop
#include<stdio.h>
int main()
{
int m,n;
printf("Enter range: ");
scanf("%d %d",&m, &n);
while (m<=n)
{
if(m%2!=0) printf("%d ",m);
++m;
}
return 0;
}Output:-
Enter range: 5 15 5 7 9 11 13 15
Print Odd Numbers using the do-while loop
#include<stdio.h>
int main()
{
int m,n;
printf("Enter range: ");
scanf("%d %d",&m, &n);
do
{
if(m%2!=0) printf("%d ",m);
++m;
} while(m<=n);
return 0;
}Output:-
Enter range: 10 20 11 13 15 17 19
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