c2-Branching structure

//

Main.m

C2_ Branching structure

//

Created by Dllo on 15/7/1.

Copyright (c) 2015 Zhozhicheng. All rights reserved.

//

#import <Foundation/Foundation.h>

Write a macro definition

Macro definitions are used to replace code

#define PI 2.15

A macro definition is a substitution of the previous macro definition for the name of the subsequent content

Enumeration

Enum Season {

Spring

Summer

Autumn

Winter

};

int main (int argc, const char * argv[]) {

Define a variable of type bool

BOOL isTrue = NO;

BOOL is selected

BOOL isSelected = YES;

printf ("%d\n", isSelected);

printf ("%g\n", PI);

Relational operators < <= > >= = = =

BOOL isTrue = 3 > 5;

//

logical operators

int a = 10;

//

BOOL isTrue = 3 > 5 && ++a;

printf ("%d\n", a);

Logic: The entire expression is true only if both sides of the equation are present, and if the first condition is false, then the second condition is not executed, called the logic and short-circuit problem

int a = 10;

BOOL isTrue = 3 < 5 | | ++a;

printf ("%d\n", a);

Logical OR: As long as one condition is true, the entire expression is true, and if the first condition is already true, the second condition is not executed, called a logical or short-circuit condition

If the first form of

int a = 10;

if (= = a) {

printf ("Set up, execute print statement \ n");

//    }

//

char a = 0;

scanf ("%c", &a);

if (a = = ' m ') {

printf ("Male \ n");

} else{

printf ("Female \ n");

//    }

int a = 0;

Input Join scanf

scanf ("%d", &a);

if (a% = = 0 | | A%4 = 0 && a% 100! = 0) {

printf ("Leap year \ n");

} else{

printf ("Not a leap year \ n");

//    }

//

int year = 0;

scanf ("%d", &year);

BOOL result1= Year% 400 = = 0;

BOOL result2= year%4 ==0 && year% 100! = 0;

if (result1 | | result2 = = 1) {

printf ("Leap year \ n");

//

} else{

printf ("Not a leap year \ n");

//    }

char c = 0;

scanf ("%c", &c);

if (' w ' = = c) {

printf ("Female \ n");

}else if (' m ' ==c) {

printf ("Male \ n");

//

}else {

printf ("Shemale \ n");

//    }

If the condition after the parentheses cannot be added;

char c = 0;

scanf ("%c", &c);

if (c >= ' 0 ' && C <= ' 9 ') {

printf ("This is digital\n");

}else if (c >= ' A ' && C <= ' Z ') {

printf ("This was capital letter\n");

}else if (c >= ' a ' && c <= ' z ') {

printf ("This is letter\n");

}else{

printf ("other\n");

//    }

//

Switch case

int a = 0;

scanf ("%d", &a);

Switch (a) {

Case 901:

printf ("Finance department \ n");

Break

Case 902:

printf ("Security Department \ n");

Break

Case 903:

printf ("Technical department \ n");

Break

Case 904:

printf ("HR \ n");

Break

Case 905:

printf ("Logistic division \ n");

Break

//

Default

printf ("Please re-enter \ n");

Break

//    }

The switch stop flag is whether the Case,default has a break, or the last line of code that runs to the switch will stop

int a = 0;

scanf ("%d", &a);

Switch (a) {

Case 1:

printf ("spring\n");

Break

Case 2:

printf ("summer\n");

Break

Case 3:

printf ("autumn\n");

Break

Case 4:

printf ("winter\n");

Break

//

//

Default

Break

//    }

//

//

Print the contents of the enumeration

printf ("%d\n", spring);

printf ("%d\n", summer);

printf ("%d\n", autumn);

printf ("%d\n", winter);

//

Enumeration starts from 0 by default

The function of an enumeration is to add readability to the code, and each of the enumerations represents an integer.

In the case of switch cases, replace with an enumeration

int a = 0;

scanf ("%d", &a);

Switch (a) {

Case Spring:

printf ("spring\n");

Break

Case Summer:

printf ("summer\n");

Break

Case Autumn:

printf ("autumn\n");

Break

Case Winter:

printf ("winter\n");

Break

//

//

//

Default

Break

//    }

//

int a = 10,b = 20;

if (a > B) {

printf ("%d\n", a);

}else{

printf ("%d\n", b);

//    }

//

Conditional operators

int a = ten, b = 20,d = 15;

int c = a > B? A:B;

c = c > d? C:d;

printf ("%d\n", c);

//

return 0;

}

c2-Branching structure