C语言函数

Posted 2020-07-26 新起点1

 

 

#include <stdio.h>
int main()
{
    int count1 =1;
    do{
        int count2 =0;
        ++count2;

        printf("\ncount1=%d count2=%d",count1,count2);
        count1++;
    }while (count1<=8);
    
    printf("\n count1=%d\n",count1);
    return 0;
}

 

 

 

不等价于下面这个，尽管两个输出一样

 

#include <stdio.h>
int main()
{
    int count1 =1;
    do{
        int count2 =0;
        ++count2;
        printf("\ncount1=%d count2=%d",count1,count2);
        
    }while (++count1<=8);
    
    printf("\n count1=%d\n",count1);
    return 0;

}

 详情见下面这个例子

 

#include <stdio.h>
int main(void)
{
    int count= 0;
    do{
        int count =0;
        ++count ;
        printf("\n count=%d",count );
    }
    while (++count<=8);                                                
    
    printf("\n count =%d\n",count );
    return 0;
}    

/*

count=0

  count=0
  count=1 dayin
  count=1<=8

  count=0
  count=1 dayin
 !! count=2<=8

...

  count=0
  count=1  dayin
  count=8<=8 

  count=0
  count=1  dayin
  count=9   wo tiao

  count=9  shuchu



关键在于while 中的count 和do while 里面的不是一回事，while 使用的是那个外面的，do{}的count出了括号就死了
作用域就是这么回事，以大括号为界限，出来就死。   生存期就是，就活一轮，下一轮就重生

*/

 

#include <stdio.h>
float average(float x ,float y)
{
    return (x+y)/2.0f;
}

int main (void)
{
    float value1=0.0F;
    float value2=0.0F;
    float value3=0.0F;
    
    
    printf("Enter two floating-point values separated by blanks:\n");
    scanf("%f %f",&value1,&value2);
    value3=average (value1,value2);
    printf("\n The average is:%f\n",value3);
    return 0;
    
}/*  函数调用例子*/

#include <stdio.h>
float average(float x  ,float y);/* 也可以写做  float average (float ,float);    */

int main (void)
{
    float value1=0.0F;
    float value2=0.0F;
    float value3=0.0F;
    
    
    printf("Enter two floating-point values separated by blanks:\n");
    scanf("%f %f",&value1,&value2);
    value3=average (value1,value2);
    printf("\n The average is:%f\n",value3);
    return 0;
    
}

float average(float x ,float y)
{
    return (x+y)/2.0f;
}