(C Programming Tutorials)
C for Loop
In this tutorial, you will learn to create for loop in C programming with the help of examples.
In programming, a loop is used to repeat a block of code until the specified condition is met.
C programming has three types of loops:
- for loop
- while loop
- do…while loop
We will learn about for
loop in this tutorial. In the next tutorial, we will learn about while
and do...while
loop.
for Loop
The syntax of the for
loop is:
for (initializationStatement; testExpression; updateStatement)
{
// statements inside the body of loop
}
How for loop works?
- The initialization statement is executed only once.
- Then, the test expression is evaluated. If the test expression is evaluated to false, the
for
loop is terminated. - However, if the test expression is evaluated to true, statements inside the body of
for
loop are executed, and the update expression is updated. - Again the test expression is evaluated.
This process goes on until the test expression is false. When the test expression is false, the loop terminates.
To learn more about test expression (when the test expression is evaluated to true and false), check out relational and logical operators.
for loop Flowchart
Example 1: for loop
// Print numbers from 1 to 10
#include <stdio.h>
int main(){
int i;
for (i = 1; i < 11; ++i)
{
printf("%d ", i);
}
return 0;
}
Output
1 2 3 4 5 6 7 8 9 10
- i is initialized to 1.
- The test expression
i < 11
is evaluated. Since 1 less than 11 is true, the body offor
loop is executed. This will print the 1 (value of i) on the screen. - The update statement
++i
is executed. Now, the value of i will be 2. Again, the test expression is evaluated to true, and the body of for loop is executed. This will print 2 (value of i) on the screen. - Again, the update statement
++i
is executed and the test expressioni < 11
is evaluated. This process goes on until i becomes 11. - When i becomes 11, i < 11 will be false, and the
for
loop terminates.
Example 2: for loop
// Program to calculate the sum of first n natural numbers
// Positive integers 1,2,3...n are known as natural numbers
#include <stdio.h>
int main(){
int num, count, sum = 0;
printf("Enter a positive integer: ");
scanf("%d", &num);
// for loop terminates when num is less than count
for(count = 1; count <= num; ++count)
{
sum += count;
}
printf("Sum = %d", sum);
return 0;
}
Enter a positive integer: 10 Sum = 55
The value entered by the user is stored in the variable num. Suppose, the user entered 10.
The count is initialized to 1 and the test expression is evaluated. Since the test expression count<=num
(1 less than or equal to 10) is true, the body of for
loop is executed and the value of sum will equal to 1.
Then, the update statement ++count
is executed and the count will equal to 2. Again, the test expression is evaluated. Since 2 is also less than 10, the test expression is evaluated to true and the body of for
loop is executed. Now, the sum will equal 3.
This process goes on and the sum is calculated until the count reaches 11.
When the count is 11, the test expression is evaluated to 0 (false), and the loop terminates.
Then, the value of sum
is printed on the screen.
We will learn about while
loop and do...while
loop in the next tutorial.
Disclaimer: The information and code presented within this recipe/tutorial is only for educational and coaching purposes for beginners and developers. Anyone can practice and apply the recipe/tutorial presented here, but the reader is taking full responsibility for his/her actions. The author (content curator) of this recipe (code / program) has made every effort to ensure the accuracy of the information was correct at time of publication. The author (content curator) does not assume and hereby disclaims any liability to any party for any loss, damage, or disruption caused by errors or omissions, whether such errors or omissions result from accident, negligence, or any other cause. The information presented here could also be found in public knowledge domains.
Learn by Coding: v-Tutorials on Applied Machine Learning and Data Science for Beginners
Latest end-to-end Learn by Coding Projects (Jupyter Notebooks) in Python and R:
All Notebooks in One Bundle: Data Science Recipes and Examples in Python & R.
End-to-End Python Machine Learning Recipes & Examples.
End-to-End R Machine Learning Recipes & Examples.
Applied Statistics with R for Beginners and Business Professionals
Data Science and Machine Learning Projects in Python: Tabular Data Analytics
Data Science and Machine Learning Projects in R: Tabular Data Analytics
Python Machine Learning & Data Science Recipes: Learn by Coding
R Machine Learning & Data Science Recipes: Learn by Coding
Comparing Different Machine Learning Algorithms in Python for Classification (FREE)
There are 2000+ End-to-End Python & R Notebooks are available to build Professional Portfolio as a Data Scientist and/or Machine Learning Specialist. All Notebooks are only $29.95. We would like to request you to have a look at the website for FREE the end-to-end notebooks, and then decide whether you would like to purchase or not.