C Language-switch statements

Switch (the value of an expression) {

Case 1:

Statement 1

Break

Case 2:

Statement 2

Break

Case 3:

Statement 3

Break

Case 4:

Statement 4

Break

......

Default

Default statement

Break

1, suitable for the discrete value of the switch judgment, can be converted into a continuous range

2, pay attention to case penetrating, break the use.

3. You can define each case value as an enum enumeration or use a macro definition to define an alias

1. Use switch statement completion: Enter a simple two-digit subtraction operation, using switch to calculate the value of the equation in various cases by converting the subtraction notation, which is a simple calculator:

intb; floatC; CharSign ; printf ("Please enter the number to be calculated:"); scanf ("%d",&a); GetChar ();    After entering the first digit, press ENTER to confirm that using GetChar to read the sign will be wrong to read the carriage return, so first use GetChar to read this character. printf ("Please enter the operation to be performed:"); Sign=GetChar (); printf ("Please enter the number to be calculated:"); scanf ("%d",&b); Switch(sign) { Case '+': C=a+b;  Break;  Case '-': C=a-b;  Break;  Case '*': C=a*C;  Break;  Case '/':            if(b) {C=a/b; }Elseprintf ("the divisor cannot be 0\n"); } printf ("%d%c%d=%f\n", a,sign,b,c);

2. Use the Helen formula to calculate the area of the triangle. The area of Helen's formula is, where p= (A+b+c)/2,a,b,c is a triangular three-edged length.

Note: This procedure should first determine whether the input of the three sides of the triangle is greater than the third side, the difference between the two sides is less than the third side of the condition, if not meet the conditions, it is not a triangle, can not use the Helen formula down calculation, the program ignores this judgment, assuming that three side length in line with the edge of the triangle This judgment is reflected in the next procedure.

float A,b,c,p,s;    printf (" please input triangle three edge length: \ n");    scanf ("%f%f%f", &a, &b, &c);         = (a+b+c)/2;     = sqrt (double) p * (P-A) * (p-b) * (P-c));        printf (" the area of the triangle is%.2f\n", s);

3, input triangle three side length, judge whether the triangle is right triangle or equilateral, isosceles, General triangle. Complete with if nesting.

floatA, B, C; printf ("please input triangle three edge length: \ n"); scanf ("%f%f%f", &a, &b, &c); if(a>0&& b>0&& c>0) {        if(a+b>c && a+c>b && b+c>a) {if(A==b && b==c) {printf ("input is a positive triangle \ n"); }Else if(a==b | | b==c | | a==c) {               if(a*a==b*b+c*c | | a*a+b*b==c*c | | a*a+c*c==b*b) printf ("input is isosceles right triangle \ n"); Elseprintf"input is isosceles triangle \ n"); }Else if(a*a==b*b+c*c | | a*a+b*b==c*c | | a*a+c*c==b*b) {printf ("input is right triangle \ n"); }Elseprintf"input is a general triangle \ n"); }        Elseprintf"input is not a triangle \ n"); }Else{printf ("input is not a triangle \ n"); }

4. Enter a percentile score, and use the switch statement to convert this score to the A,b,c,d hierarchy and output:

int score=0;
Char grade= ' 0 ';
scanf"%d",&score); if(score>=0&& score<= -) {        Switch(score/Ten) {             Case Ten:             Case 9: Grade='A';  Break;  Case 8: Grade='B';  Break;  Case 7: Grade='C';  Break;  Case 6: Grade='D';  Break; default: Grade='N';  Break; } printf ("the grade is converted to%c!!! \ n", grade); }Elseprintf ("Enter an illegal!!!! \ n");

C Language-switch statements