Loops in C

INTRODUCTION

 Loops can execute a block of code as long as a specified condition is reached. Loops are handy because they save  time, reduce errors, and they make code more readable.

TYPES OF LOOPS

1.WHILE LOOP :Repeats a statement or group of statements until a given condition is true. It  testes the condition before executing the loop body. 

3 Steps to write while loop: 

1)Initialization, 2)Condition check, 3)Increment/Decrement

Syntax :

while (condition)

{

statements

}

                                                   

 Flowchart

Example

Question : Print 1 to 10 numbers

code :

#include<stdio.h>

int i=1;

int main()

{

while(i<=10)

{

printf("%d",i);

i++;

}

}

output: 1 2 3 4 5 6 7 8 9 10

2.FOR LOOP :Execute a sequence of statements multiple times and reduce the code that manages the loop variable.

3 Steps to write for loop: 

1)Initialization, 2)Condition check, 3)Increment/Decrement

Syntax :

for(initialization; condition check; increment/decrement )

{

statements

}

                                                                      Flowchart

Example

Question : Print 1 to 10 numbers

code :

#include<stdio.h>

int i;

int main()

{

for(i=1; i<=10; i++)                   // (if i want to print 10 to 1 then i=10; i>=1; i-- )

{

printf("% d \n", i);

}

}

output: 1 2 3 4 5 6 7 8 9 10

3.NESTED FOR LOOP :You can use one or more loops inside the main loop.

Syntax :

 for(init; condition check; inc/dec)

         {

             for(init; condition check; inc/dec)

                {

                        for(init; condition check; inc/dec)

                }

         }

                                                                              Flowchart

Example

code :

#include<stdio.h>

int i,j;

int main()

{

  for(i=0; i<=2; i++)                 

    {

        for(j=0; j<=2; j++)

           {

               printf("% d  %d ", i, j);

            }

     }

}

output : 00 01 02 10 11 12 20 21 22