IPhone開發之C基礎(二)

今天我們主要說的還是C的基礎,這次我們主要由代碼來具體說明。

首先來說說最頭疼的問題a=i++與a=++i的區別,a=i++是先賦值再自增,a=++i是先自增再賦值

 

  int i = 5;

 

   int b = i++;

   int c = i;

 

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

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

 

 

   int a = ++i + (b++);

 

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

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

 

   int d = i+b;

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



 

 

printf("**********************\n");

 

   int z=1;

   int j =z++;

   //j=1  z=2

   printf("z = %d",z);

   printf("j = %d\n",j);

   j = ++z;

   //j=3  z=3

   printf("z = %d",z);

   printf("j = %d\n",j);

   j = z--;

   //j=3  z=2

   printf("z = %d",z);

   printf("j = %d\n",j);

   j = --z;

   //j=1  z=1

   printf("z = %d",z);

   printf("j = %d\n",j);

 

 

printf("**********************\n");


 


 

任何語言都會用到判斷的,下面先說說if  else

printf("**********************\n");

 

 

i = 0;

if(i){

   printf("true\n");

}else{

   printf("false\n");

}

printf("**********************\n\n\n\n\n");

不使用中間值判斷三個數最大的

printf("**********************\n\n\n\n\n");

 

a = 8;

b = 4;

c = 1;

int max = 0;

if(a>b){

   if(a>c){

      max = a;

   }else{

      max = c;

   }

}else{

   if(b<c){

      max = c;

   }else{

      max = b;

   }

}

printf("最大:%d\n",max);

printf("**********************\n\n\n");

switch語句

printf("**********************\n\n\n");

 

char char_grade;

printf("請輸入:");

//scanf("%c",&char_grade);

 

switch(char_grade){

case 'A':

   printf("90-100\n");

   break;

case 'B':

   printf("80-90\n");

   break;

case 'C':

   printf("70-80\n");

   break;

default:

   printf("請重新輸入輸入:\n");

break;

 

}

 

printf("**********************\n\n\n");

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