C switch statement
Description
To take one of a number of possible actions. switch is preferred over multiple if...else statements.
Syntax
The general form of a switch statement is
switch(switch_expr)
{// w w w . j a v a 2 s. com
case constant expr1 : Statement1;
Statement2;
break;
case constant expr1 : Statement3;
Statement4;
break;
.....
default : Statement5;
Statement6;
break;
}
Example for switch statement
The clause 'default' is optional.
#include <stdio.h>
// ww w . ja va 2 s. co m
main(){
int i,n = 5;
for(i = 1; i<n; i= i+1){
switch(i%2)
{
case 0 : printf("the number %d is even \n",i);
break;
case 1 : printf("the number %d is odd \n",i);
break;
}
}
}
The code above generates the following result.
Two cases, one action
#include <stdio.h>
//from w ww .j a va 2s . c om
int main(void)
{
char answer = 0;
printf("Enter Y or N: ");
scanf(" %c", &answer);
switch (answer)
{
case 'y': case 'Y':
printf("\nYou responded in the affirmative.");
break;
case 'n': case 'N':
printf("\nYou responded in the negative.");
break;
default:
printf("\nYou did not respond correctly...");
break;
}
return 0;
}
The code above generates the following result.
Nest if statement in case statement
#include <stdio.h>
#include <ctype.h>
/*from w w w. j av a 2 s.c o m*/
int main(void)
{
double number1 = 3.0;
double number2 = 4.0;
char operation = '+';
char reply = 0;
switch(operation)
{
case '+':
printf("= %lf\n", number1 + number2);
break;
case '-':
printf("= %lf\n", number1 - number2);
break;
case '*':
printf("= %lf\n", number1 * number2);
break;
case '/':
if(number2 == 0)
printf("\n\n\aDivision by zero error!\n");
else
printf("= %lf\n", number1 / number2);
break;
case '%':
if((long)number2 == 0)
printf("\n\n\aDivision by zero error!\n");
else
printf("= %ld\n", (long)number1 % (long)number2);
break;
default:
printf("\n\n\aIllegal operation!\n");
break;
}
return 0;
}
The code above generates the following result.
