The basic course of C language (iii) input and output functions and control flow statements (17)

1.3.3 Switch statement
When writing a program, often encountered by the different circumstances of the multiple-path problem, then can be nested IF-ELSE-IF statements to implement, but If-else-if statement use inconvenient, and error prone. In this case, the Turbo C2.0 provides a switch statement. The format of the switch statement is:
Switch (variable)
{
CASE constant 1:
Statement 1 or null;
Case constant 2:
Statement 2 or NULL;
.
.
.
case constant N;
statement n or NULL;
Default
Statement n+1 or empty;
}
When executing a switch switch statement, the variable is compared to the constant after the case, and if one is equal, the statement under the constant is executed, and if not equal to any of the constants, the statement following the default is executed.
Attention:
A variable in 1.switch can be a numeric value, or it can be a character.
2. You can omit some cases and default.
3. Each case or default statement can be a statement body, but it does not need to be enclosed with "{" and "}".
In the following example, the variable in the switch is an integral type.
Example 19:
Main ()
{
int test;
for (test=0; test<=10; test++)
{
Switch (test)/* variable is integer number of switches statement */
{
Case 1:
printf ("%d\n", test);
Break /* EXIT Switch statement * *
Case 2:
printf ("%d\n", test);
Break
Case 3:
printf ("%d\n", test);
Break
Default
Puts ("Error");
Break
}
}
}
In the following example, the variable in the switch is character type.
Example 20:
#include <stdio.h>
Main ()
{
char c;
while (c!=27)/* Loop until the ESC key is closed * *
{
C=getch (); /* From the keyboard does not echo receive a character * *
Switch (c)
{
Case ' a ':/* receive the character ' a ' * *
Putchar (c);
Break /* EXIT Switch statement * *
Case ' B ':
Putchar (c);
Break
Default:/* received word Fu Fei ' A ' and ' B ' *
Puts ("Error");
Break
}
}
}