使用while(x)

Question

#include<stdio.h>
#include<conio.h>

/* Function Declaration
int pal(int x); */
/*Declaring Second Function*/

int rev(int x);

int main()
{
    int a, b, c;
    clrscr();

    printf("Enter The Number Which You Want To Check Is Palindrome Or Not\n");
    scanf("%d", &a);

    b = rev(a);
    printf("%d", b);

    if(b == a) {
        printf("%d Is A Palindrome Number", a);
    } else {
        printf("%d Isn't A Plaindrome Number", a);
    }

    getch();
    return(0);
}

int rev(int x)
{
    int d = 0;

    while(x) {
        d = d * 10 + x % 10;
        x = x / 10;
    }
    return(d);
}

我没有得到while(x)陈述的使用.我的意思是,我们用while循环附加一些条件,即while(x!=0)独立while(x)意味着什么.

Answer 1

while (x) 是相同的 while (x != 0)

对于整数数据类型,0是false&等等true.因此while (x),while(true)将为所有人评估x != 0.

同样,你也会遇到像while(!x)或的表达式if(!x)

如果x有值不为零,则x是true&!x是false.如果x有值0,则x是false&!x是true.

所以写作(!x)和写作一样(x == 0)

您还将看到与指针类似的用法.对于指针p,(p)与...相同(p != NULL)且(!p)相同(p == NULL).