Untitled Quiz

Loop Control Statements

• Loop statements in C allow for the repetition of a certain block of code multiple times.
• The three main types of loops are:
  • for loop
  • while loop
  • do...while loop
• Jump statements alter the flow of a program. The most common jump statements are:
  • continue
  • break
  • goto
  • continue is used to skip the remaining statements in the current iteration within the loop and move to the next iteration.
  • break is used to terminate the execution of the loop or switch-case statement.
  • goto is used to jump unconditionally to a specific label within the same function.

For Loop

• The for loop is generally used when the number of iterations is known beforehand.
• Syntax:

for (initialization; test expressions; update expression)
{
   statements; 
}

• Initialization: This statement is executed only once at the beginning of the loop to initialize the loop control variable/counter.
• Test Expression: This expression is evaluated in each iteration of the loop.
  • If the expression is true (non-zero), the loop body is executed, and the update expression is executed.
  • If the expression is false (zero), the loop terminates, and the program control jumps to the next statement after the "for" loop.
• Update Expression: This expression is used to update the loop control variable after each iteration of the loop.
• The for loop repeats steps 2 and 3 until the test expression becomes false or the loop is terminated using a break statement.

Example

• This is a simple example of a C program demonstrating a for loop that adds a series of numbers until the user enters a specific number:

#include <stdio.h>

int main(){
    int n, counter, sum = 0;
    printf("Enter integer number: ");
    scanf("%d", &n);
    for(counter=1; counter <= n; counter++) {
        sum += counter;
    }
    printf("Sum of the first %d natural numbers is: %d\n", n, sum);
    return 0;
}

• In this example:
  • #include <stdio.h> is a preprocessor directive that includes the standard input/output library which provides functions like printf and scanf.
  • int main() is the function where the program execution begins.
  • int n, counter, sum = 0; declares three integer variables: n to store the user input, counter to act as the loop counter, and sum to store the accumulated sum.
  • printf("Enter integer number: "); displays a message asking the user to enter an integer.
  • scanf("%d", &n); reads the integer entered by the user and stores it in the n variable.
  • for(counter = 1; counter <= n; counter++) { ... } initiates the for loop:
    • The initialization (counter = 1;) sets the initial value of the loop counter to 1.
    • The test expression (counter <= n;) checks if the current value of counter is less than or equal to the user-input n. If it is, the loop continues to execute.
    • The update expression (counter++;) increments the counter variable by 1 after each iteration.
    • The loop body (sum += counter;) adds the current value of counter to the sum variable in every iteration.
  • printf("Sum of the first %d natural numbers is: %d\n", n, sum); displays the sum of the first n natural numbers.
  • return 0; indicates that the program executed successfully.