指针之间的字符串长度

Question

我遇到了一个小问题,需要一些帮助:

如果我有一个已分配的字符缓冲区,并且我有一个位于此缓冲区内的起点和终点,并且我想要这两点之间的长度,我该如何找到它？

即

char * buf; //malloc of 100 chars
char * start; // some point in buff
char * end; // some point after start in buf

int length = &end-&start? or &start-&end? 
//How to grab the length between these two points.

谢谢

Answer 1

只是

length = end - start;

没有&符号和演员阵容.C指针算术允许此操作.

Answer 2

它只是后一个指针减去前面的指针.

int length = end - start;

验证和示例代码如下:

int main(int argc, char* argv[])
{
    char buffer[] = "Its a small world after all";
    char* start = buffer+6;  // "s" in SMALL
    char* end   = buffer+16; // "d" in WORLD

    int length = end - start;

    printf("Start is: %c\n", *start);
    printf("End is: %c\n", *end);
    printf("Length is: %d\n", length);
}