C 反向字符串[暂停]

Question

I have the following code where Index is defined as length- 1. It prints an extra space in the beginning if I dont include the - 1. Why is the -1 required in the code?

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
   char s[200];
   int index, lenght;

   printf("Input a string\n");
   gets(s);

   // Calculating string length
   length = strlen(s);
    index=length-1;
   while (index >=0) {

    printf("%c", s[index]);
    index--;
   }
   printf("\n");
   return 0;
}

转载于:https://stackoverflow.com/questions/53038637/c-reverse-string

Answer 1

Indexes always start from 0. So if strlen() function returns the length x that means its length is x and you have to iterate from 0 to x-1. Thats why you have to include -1. On index x there will be some garbage or space.