switch case c

switch Statement (C) – msdn.microsoft.com

The latest version of this topic can be found at switch Statement (C). The switch and case statements help control complex conditional and branching operations. The switch statement transfers control to a statement within its body. Syntax. selection-statement:

Syntax

switch( c ){  case ’A’:    capa++;Was this helpful?Thanks! Give more feedback

switch statement in C – Tutorials Point

Each value is called a case, and the variable being switched on is checked for each switch case. Syntax The syntax for a switch statement in C programming language is …

Switch Case in C and C++ – Cprogramming.com

Learn how to use the switch-case structure in C++, including an example menu program.

C switchcase Statement – Programiz

If a programmer has to choose one among many alternatives ifelse can be used but, this makes programming logic complex. This type of problem can be handled in C programming using switchcase statement

switch Statement (C++) – msdn.microsoft.com

A case or default label can only appear inside a switch statement. The constant-expression in each case label is converted to the type of expression and compared with expression for equality. Control passes to the statement whose case constant-expression matches the value of expression .

Switch Case statement in C++ with example – …

Switch case statement is used when we have multiple conditions and we need to perform different action based on the condition. When we have multiple conditions and we need to execute a block of statements when a particular condition is satisfied. In such case either we can use lengthy if..else-if statement or switch

How can I use ranges in a switch case statement in C

In the C programming language the case statement used in a switch() statement must specify a value that the compiler can turn into a constant in some way. Each of the values used in the case statements must be unique within the scope of the switch() .

The GCC compiler supports, as a language extension , case ranges like: switch(i) {
case 0 9: return true;
default: return false;
}
This language extension is also accepted by Clang/LLVM . So use it if you can afford restricting your code to GCC & Clang compilers. See also this . I have no idea why this extension was not included in C11 standard.16
Option 1: use case 0 for 0-9 , case 1 for 11-20 and so on. Option 2: use if Option 3: Another shabby way is using fall through cases like this: #include

int main(void) {
int i=1;

for(i=1;i<=25;i++)
{
switch(i)
{
case 1:
case 2:
case 3:
case 4:
case 5:
case 6:
case 7:
case 8:
case 9:
case 10:
printf("%d is in between 1-10\n", i);
break;

case 11:
case 12:
case 13:
case 14:
case 15:
case 16:
case 17:
case 18:
case 19:
case 20:
printf("%d is in between 11-20\n", i);
break;

default:
printf("%d is above 20\n", i);
}
}
return 0;
}
Output: 1 is in between 1-10
2 is in between 1-10
3 is in between 1-10
4 is in between 1-10
5 is in between 1-10
6 is in between 1-10
7 is in between 1-10
8 is in between 1-10
9 is in between 1-10
10 is in between 1-10
11 is in between 11-20
12 is in between 11-20
13 is in between 11-20
14 is in between 11-20
15 is in between 11-20
16 is in between 11-20
17 is in between 11-20
18 is in between 11-20
19 is in between 11-20
20 is in between 11-20
21 is above 20
22 is above 20
23 is above 20
24 is above 20
25 is above 20
https://ideone.com/Cw6HDO4
void SwitchDemo(int value)
{
switch(value / 10)
{
case 0: ; break; // 0 – 9
case 1: ; break; // 10 – 19

}
}
or, specific to the question ranges: void SwitchDemo(int value)
{
switch((value-1) / 10)
{
case 0: ; break; // 1 – 10
case 1: ; break; // 11 – 20

}
}4
C doesn’t support case values other than single integers (or integer-like things — characters, enumeration values). So your options are: As suggested by pzaenger in a now-deleted comment: transform the number you’re working with into something you can switch on (in this case, divide by 10). Multiple case statements (taking advantage of fallthrough): case 1: case 2: case 3: case 10: do_something(); Use if rather than case .0You won’t be able to do this in standard C with a switch-case statement. (as other answers have pointed out, some compiler have non-standard extensions to enable this) Instead, I recommend making a data-structure such as: struct RangeData
{
int start;
int end;
void (*func)(int);
};

RangeData ranges[] = { { 1, 10, Handle10s },
{ 20, 30, Handle20s },
{5000, 10000, HandleBigNumbers} };
Then it should be very easy to make a tiny loop that cycles through, finds the proper range, and calls the proper function. void DoNumber(int value)
{
for(int i=0; i<ARRAYSIZE(ranges); ++i)
{
if (ranges[i].start <= value && value <= ranges[i].end)
{
ranges[i].func(value);
}
}
}0
In the C programming language the case statement used in a switch() statement must specify a value that the compiler can turn into a constant in some way. Each of the values used in the case statements must be unique within the scope of the switch() . The default keyword indicates the default if none of the case statements match the expression in the switch() statement. As an aside, check out Duff’s Device to show an interesting use of switch() and case . See How does Duff’s device work? So the following shows several examples of proper case statements in a switch() : #define XXVAL 2
#define CASETEST(x) (x + 5)

int iValue;
// set the value of the variable iValue at some point
switch (iValue) {
case 0:
// do the case if iValue == 0
break;
case XXVAL:
// do the case if iValue == XXVAL
break;
case CASETEST(3):
// do the case if iValue == CASETEST(3)
// works because preprocessor generates the source text which is
// then compiled and the expression can be resolved to a constant
break;
case CASETEST(5) * 2:
// do the case if iValue == CASETEST(5) * 2
// works because preprocessor generates the source text which is
// then compiled and the expression can be resolved to a constant
break;
default:
break;
}
What you can do if you still want to use a switch() with ranged case statements is to provide some mechanism to fold the expression into one or more specific constant values. So in a simple, trivial example you could do something like the following. This is a trivial case to show the technique which ends up making the logic of the simple if statements opaque. This technique can be useful for complex decisions and classification that can be folded into a simple set of constants. int foldit (int iValue)
{
if (iValue < 5000) return 0;
else if (iValue < 10000) return 1;
else if (ivalue < 20000) return 2;
else return 9999; // triggers the default part of the switch
}

switch (foldit(iValue)) {
case 0:
// do what is needed for up to but not including 5000
break;
case 1:
// do what is needed for 5000 up to but not including 10000
break;
case 2:
// do what is needed for 10000 up to but not including 20000
break;
default:
// handle anything else
break;
}
Where the fold approach can be helpful is when you have several different results perhaps using a filter to try to classify a data item. #define type1 0x00001
#define type2 0x00002
#define type3 0x00004
#define type4 0x00008

struct datatype {
int iVal;
int jVal;
};

unsigned long is_a_type1(struct datatype * thing)
{
unsigned long retVal = 0; // initialize to not a type1, set to type1 if turns out to be
// do checks for the type and if so set retVal to type1 if it matches
return retVal;
}

unsigned long is_a_type2(struct datatype * thing)
{
unsigned long retVal = 0; // initialize to not a type2, set to type2 if turns out to be
// do checks for the type and if so set retVal to type2 if it matches
return retVal;
}

unsigned long is_a_type3(struct datatype * thing)
{
unsigned long retVal = 0; // initialize to not a type3, set to type3 if turns out to be
// do checks for the type and if so set retVal to type3 if it matches
return retVal;
}

unsigned long is_a_type4(struct datatype * thing)
{
unsigned long retVal = 0; // initialize to not a type4, set to type4 if turns out to be
// do checks for the type and if so set retVal to type4 if it matches
return retVal;
}

unsigned long classify (struct datatype *thing)
{
unsigned long ulTestResult = 0;

// test to see if this is a type1 thing
ulTestResult |= is_a_type1(thing);

// test to see if this is a type2 thing
ulTestResult |= is_a_type2(thing);

// test to see if this is a type3 thing
ulTestResult |= is_a_type3(thing);

// test to see if this is a type4 thing
ulTestResult |= is_a_type4(thing);

return ulTestResult;
}

int main ()
{
struct datatype myThing;
// other source code then
switch (classify(&myThing)) {
case type1 | type2 | type3:
// do stuff if this is a type1, type2, and type3 but not type4
// that is classify() determined that myThing matched all three types.
break;
case type1:
// do stuff if type1 which includes stuff you do for type2 as well under
// special values of myThing.
if (myThing.iVal < 50) {
case type2:
// at this point we have type2 case stuff that we do. Code above is skipped
// and the switch () will jump straight to here if classify() is type2.
//
// Also stuff we do if type1 and myThing.iVal < 50
// in other words this code is execute if classify(&myThing) is type2 or
// if classify(&myThink) is type1 and there is a special processing for myThing.iVal < 50
break; // if classify() type2 or if classify() type1 and myThing.ival = 50
break;
case type2 | type3:
// do stuff if type2 and type3 matched but none of the others.
break;
default:
// any other case
break;
}
return 0;
}0
Switch statements in c can only operate on a constant expression, the case statements cannot include dynamic comparisons. Example of something which is, and is not, a ”Constant Expression” in C? For something this simple an if/else structure could be clearer and simpler, depending on the compiler your case statement may be translated into a series of branching comparison statements anyways.

Switch case, check ranges in C# 3.5
In C++ can there be a range of values in a switch statement
c# – Switch case: can I use a range instead of a one number
int – switch case (in C)

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C# Switch Examples – Dot Net Perls

The most derived class is matched first—in this switch form, order matters.`Pattern matching, when.` We can place a condition on each case statement. This can test another variable. Here we test a local variable called secondValue on the first 2 cases. `We have repeat ”case 200” statements.

Switch Case in C# – SyntaxDB – C# Syntax Reference

A switch case is used test variable equality for a list of values, where each value is a case. When the variable is equal to one of the cases, the statements following the case are executed. A break statement ends the switch case. The optional default case is for when the variable does not equal any of the cases.

Switch statement – Wikipedia

When implemented with fall-through as the default path, switch/case statements are a frequent source of bugs among even experienced programmers, given that, in practice, the ”break” is almost always the desired path, but not the default behavior of the switch/case construct (at least in C and Java).

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