Wednesday, November 12, 2014

C Programming break and continue Statement

C Programming break and continue Statement

There are two statements built in C programming, break; and continue; to alter the normal flow of a program. Loops perform a set of repetitive task until text expression becomes false but it is sometimes desirable to skip some statement/s inside loop or terminate the loop immediately without checking the test expression. In such cases, break and continue statements are used. The break; statement is also used in switch statement to exit switch statement.

break Statement

In C programming, break is used in terminating the loop immediately after it is encountered. The break statement is used with conditional if statement.

Syntax of break statement

break;
The break statement can be used in terminating all three loops for, while and do...while loops.
Flowchart of break statement in C programming.
The figure below explains the working of break statement in all three type of loops.
working of break statement in C programming in for, while and do...while loops

Example of break statement

Write a C program to find average of maximum of n positive numbers entered by user. But, if the input is negative, display the average(excluding the average of negative input) and end the program.

/* C program to demonstrate the working of break statement by terminating a loop, if user inputs negative number*/
# include <stdio.h>
int main(){
   float num,average,sum;
   int i,n;
   printf("Maximum no. of inputs\n");
   scanf("%d",&n);
   for(i=1;i<=n;++i){
       printf("Enter n%d: ",i);
       scanf("%f",&num);
       if(num<0.0)
       break;                     //for loop breaks if num<0.0
       sum=sum+num;
}
  average=sum/(i-1);       
  printf("Average=%.2f",average);
  return 0;
}
Output
Maximum no. of inputs
4
Enter n1: 1.5
Enter n2: 12.5
Enter n3: 7.2
Enter n4: -1
Average=7.07
In this program, when the user inputs number less than zero, the loop is terminated using break statement with executing the statement below it i.e., without executing sum=sum+num.
In C, break statements are also used in switch...case statement. You will study it in C switch...case statement chapter.

continue Statement

It is sometimes desirable to skip some statements inside the loop. In such cases, continue statements are used.

Syntax of continue Statement

continue;
Just like break, continue is also used with conditional if statement.
Flowchart of continue statement in C programming
For better understanding of how continue statements works in C programming. Analyze the figure below which bypasses some code/s inside loops using continue statement.
Working of continue statement in  C programming language

Example of continue statement

Write a C program to find the product of 4 integers entered by a user. If user enters 0 skip it.

//program to demonstrate the working of continue statement in C programming 
# include <stdio.h>
int main(){
    int i,num,product;
    for(i=1,product=1;i<=4;++i){
        printf("Enter num%d:",i);
        scanf("%d",&num);
        if(num==0)
            continue;  / *In this program, when num equals to zero, it skips the statement product*=num and continue the loop. */
        product*=num;
}
    printf("product=%d",product);
return 0;
}

Output
Enter num1:3
Enter num2:0
Enter num3:-5
Enter num4:2
product=-30

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