Value is not 1, 2, or 3

the value of i evaluated in outer switch: 10
The value of j evaluated in nested switch: 20
Exact value of i is : 10
Exact value of j is : 20 

C Loops

In C programming, loops are used to execute a block of code repeatedly until a specified condition is met. There are three main types of loops in C: for, while, and do-while. Each loop has its own syntax and use cases.

for Loop:

The for loop is used when you know how many times you want to execute a block of code. It consists of three parts: initialization, condition, and increment/decrement. syntax

for (initialization; condition; increment/decrement) {
    // Code to be executed repeatedly
}

Flowchart of for Loop

example:
wap to display number from 1 t0 10 using for loop in c

#include <stdio.h>

int main() {
    int i;

    // Using a for loop to display numbers from 1 to 10
    for (i = 1; i <= 10; i++) {
        printf("%d\n", i);
    }

    return 0;
}

In this program:

• We declare an integer variable i to use as the loop counter.
• The for loop is initialized with i = 1 to start from 1.
• The loop condition is i <= 10, meaning the loop will continue as long as i is less than or equal to 10.
• After each iteration, i is incremented by 1 (i++).
• Inside the loop, we print the value of i using printf.
• The loop continues until i reaches 10, and then the program terminates.

while Loop: The while loop is used when you want to execute a block of code as long as a condition is true. It evaluates the condition before executing the block of code.

syntax

while (condition) {
    // Code to be executed repeatedly
}

Flowchart of while loop in C

example:

1. Display your name 10 times on the screen using a while loop:

#include <stdio.h>

int main() {
    int count = 0;

    // Displaying the name 10 times using a while loop
    while (count < 10) {
        printf("Your Name\n");
        count++;
    }

    return 0;
}

2. Display the series from 10 to 1 using a while loop:

#include <stdio.h>

int main() {
    int num = 10;

    // Displaying the series from 10 to 1 using a while loop
    while (num >= 1) {
        printf("%d ", num);
        num--;
    }

    return 0;
}

3. Calculate and display the sum of odd natural numbers up to n using a while loop:

#include <stdio.h>

int main() {
    int n, sum = 0, num = 1;

    printf("Enter a number: ");
    scanf("%d", &n);

    // Calculating and displaying the sum of odd natural numbers up to n
    while (num <= n) {
        sum += num;
        num += 2; // Incrementing num by 2 to get the next odd number
    }

    printf("Sum of odd natural numbers up to %d is: %d\n", n, sum);

    return 0;
}

do-while Loop: The do-while loop is similar to the while loop, but it evaluates the condition after executing the block of code, so the block of code is guaranteed to execute at least once.

syntax

do {
    // Code to be executed repeatedly
} while (condition);

do…while Loop Flowchart

example:

1. Calculate and display the series $1,8,27,\dots$ up to the 10th term using a do-while loop:

   #include <stdio.h>
   
   int main() {
       int term = 1;
       int num = 1;
   
       // Displaying the series up to the 10th term using a do-while loop
       do {
           printf("%d ", num);
           num = num * term;
           term++;
       } while (term <= 10);
   
       return 0;
   }
   

   2. Display the series $15,9,\dots$ up to the 20th term using a do-while loop:

   #include <stdio.h>
   
   int main() {
       int term = 1;
       int num = 15;
   
       // Displaying the series up to the 20th term using a do-while loop
       do {
           printf("%d ", num);
           num = num - 6;
           term++;
       } while (term <= 20);
   
       return 0;
   }
   

   3. Display the multiplication table of any number given by the user using a do-while loop:

   #include <stdio.h>
   
   int main() {
       int num, i = 1;
   
       printf("Enter a number: ");
       scanf("%d", &num);
   
       printf("Multiplication table of %d:\n", num);
   
       // Displaying the multiplication table using a do-while loop
       do {
           printf("%d x %d = %d\n", num, i, num * i);
           i++;
       } while (i <= 10);
   
       return 0;
   }
   

   Continue Statement

   The C continue statement resets program control to the beginning of the loop when encountered. As a result, the current iteration of the loop gets skipped and the control moves on to the next iteration. Statements after the continue statement in the loop are not executed.

Syntax of continue in C

The syntax of continue is just the continue keyword placed wherever we want in the loop body.

continue;

Use of continue in C

The continue statement in C can be used in any kind of loop to skip the current iteration. In C, we can use it in the following types of loops:

• Single Loops
• Nested Loops

Using continue in infinite loops is not useful as skipping the current iteration won’t make a difference when the number of iterations is infinite.

1 2 3 5 6 7 8 
1 2 3 5 6 7 8

Example 2: C Program to use continue in a nested loop

The continue statement will only work in a single loop at a time. So in the case of nested loops, we can use the continue statement to skip the current iteration of the inner loop when using nested loops.

0 1 2 4 
0 1 2 4 
0 1 2 4

break;

break in for loop
1 2 
break in while loop
1 2

1 
1 2 
1 2 3 
1 2 3 4

0 1 2 3 4

switch(expression)
{    
case value1:
    statement_1;
    break;
    
case value2:
    statement_2;
    break;
.....
.....

case value_n:
    statement_n;
    break;
    
default:
    default statement;
}

Enter an operator (+, -), if want to exit press x: +
Enter Two Values:
10
20
10.0 + 20.0 = 30.0

#include <stdio.h>  
int main()   
{  
  int num,i=1;   
  printf("Enter the number whose table you want to print?");   
  scanf("%d",&num);  
  table:   
  printf("%d x %d = %d\n",num,i,num*i);  
  i++;  
  if(i<=10)  
  goto table;    
}

#include <stdlib.h>

void exit(int status);

#include <stdio.h>
#include <stdlib.h>

int main() {
    int num;

    printf("Enter a number: ");
    scanf("%d", &num);

    if (num < 0) {
        printf("Error: Negative number entered. Exiting program...\n");
        exit(1); // Exit with non-zero status indicating error
    }

    printf("Entered number: %d\n", num);

    return 0;
}

#include <stdio.h>  
#include <stdlib.h>  
int main ()   
{  
// declaration of the variables  
int i, num;  
printf ( " Enter the last number: ");  
scanf ( " %d", &num);  
for ( i = 1; i<num; i++)  
{  
// use if statement to check the condition  
if ( i == 6 )  
  
/* use exit () statement with passing 0 argument to show termination of the program without any error message. */  
exit(0);    
  
else  
  
printf  (" \n Number is %d", i);  
}   
return 0;  
}

Enter the last number: 10

 Number is 1
 Number is 2
 Number is 3
 Number is 4
 Number is 5

Start the execution of the program.
Exit from the program. 

Great, you did it.

#include <stdio.h>  
#include <stdlib.h>  
int main ()  
{  
int num1, num2;  
printf (" Enter the num1: ");  
scanf ("%d", &num1);  
      
printf (" \n Enter the num2: ");  
scanf ("%d", &num2);  
      
if (num2 == 0)  
{  
printf (" \n Dividend cannot be zero. ");  
      
// use EXIT_FAILURE  
exit(1);  
}  
  
float num3 = (float)num1 / (float)num2;  
printf (" %d / %d : %f", num1, num2, num3);  
  
// use the EXIT_SUCCESS  
exit(0);  
}

Enter the num1: 20
Enter the num2: 6
20 / 6 : 3.333333

2nd Run
Enter the num1: 20
Enter the num2: 6
Dividend cannot be zero

//Write a program to display numbers from 1 to 10 using goto statement
#include<stdio.h>

void main()

int i=1; 
label 1;

printf("%d\n");

1++;
 if(i<=10)
 goto label 1;
}