#include <stdio.h>

int main(int argc, const char * argv[])
{
    int n=1;
   
    for (int day = 9; day>=1; day--) {
        n = (n + 1) * 2;
        printf("第%d天摘了%d个桃子\n",day,n);
        
      
    }
    printf ("一共%d个桃子\n", n);
    return 0;
}

写的不错,不过如果加上注释就更好了

int main(int argc, const char * argv[])
{
    int peach_num = 1;//第十天桃子数量
    int day = 10;
    for (; day>1; day--) {
        printf("第%d天，peach_num = %d\n", day,peach_num);
        peach_num = (peach_num + 1) * 2;
        
    }
    printf("第%d天，peach_num = %d\n", day,peach_num);
    return 0;
}
希望对你思路有帮助