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C Programming in VS Code

Printing a message in C

Beginner's Guide to Keywords, Identifiers, Constants, Variables, Datatypes in C

Operators & Expressions in C

Input & Output Operations in C

Control Statements in C

Loops in C

Array in C

Character Array & Strings in C

User Defined Functions in C

Structure and Union in C

Pointers in C

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Loops in C

Loops: Execution of the sequence of statements repeatedly until some condition for termination is satisfied.

A looping process includes the following steps:

1) Setting the initialization of the condition variable.

2) Execution of the statements in the loop.

3) Test for a specified value of the condition variable for the execution of the loop.

4) Incrementing or updating the condition variable.

Loops in C:

1) While loop: It is an entry-controlled loop that test-condition first and then executes the body of the loop if the condition is true.

2) Do while loop: It executes the body of the loop first and then evaluates the test-condition in the subsequence while statement.

3) For loop: It is a more efficient loop structure in C programming.

Nesting of loops: Nesting of loops, that is, one loop statement within another loop statement. The nesting may continue to any desired level. C allows up to 15 levels of nesting. The outer loop controls the rows while the inner loop controls the columns.

Selecting a Loop:

1) Analyse the problem and see whether it required a pre-test or post-test loop.

2) If it requires a post-test loop, then we can use only one loop, do-while.

3) If it requires a pre-test loop, then we have two choices: while or for.

4) Decide whether the loop termination requires counter-based control or sentinel-based control.

5) Use for loop if the counter-based control is necessary.

6) Use a while loop if the sentinel-based control is necessary.

7) Note that both the counter-controlled and sentinel-controlled loops can be implemented by all three looping structures.

Jumping out of a loop: Terminates the loop and takes the program control to the statement immediately following the loop.

Skipping a part of a loop: Skips the remaining parts of the loop and takes the program control to the next loop iteration.

Loops in C

While loop:

while_loop.c


#include <stdio.h>

void main() {
    int sum = 0, count = 1, number;
    printf("Enter number to get the sum upto that number: ");
    scanf("%d", &number);
    while(count <= number) {
        sum += count; // or you write [" sum = sum + count; "]
        count++;
    }
    printf("\nSum = %d", sum);
}

Do while loop:

do_while_loop.c


#include <stdio.h>

void main() {
    int row = 1, number, value;
    printf("Enter number to get table: ");
    scanf("%d", &number);
    do {
        value = row * number;
        printf("%d x %d = %d\n", number, row, value);
        row++;
    } while(row<= 10);
}

For loop:

for_loop.c


#include <stdio.h>

void main() {
    int number, result_value = 1;
    printf("Enter a number to get the exponential value of it: ");
    scanf("%d", &number);
    for(int i = 1; i < 11; i++) {
        result_value *= number; // you can write as [" result_value = result_value * number; "]
        printf("\n%d to the power %d = %d", number, i, result_value);
    }
}

Nesting of loops:

nesting_of_loops.c


#include <stdio.h>

void main() {
    printf("Table from 1 to 10\n");
    for(int i = 1; i <= 10; i++) {
        for(int j = 1; j <= 10; j++) {
            printf("%d\t", i * j);
        }
        printf("\n");
    }
}

Skipping iteration and Jumping out of loop:

continue_break_in_loop.c


#include <stdio.h>

void main() {
    int i = 0;
    for (i = 0; i < 10; i++) {
        if(i % 2 == 0) {
            continue;
        } else if(i == 9) {
            break;
        } else {
            printf("\n%d", i);
        }
        printf("\n");
    }
}