识别years前有几个数字当字符，将这些数字转换成整数，再把整数转换成字符串，与years连接后显示出来

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

int main()
{
char ori_str[] = "You will pay $687.71 every month for 15 years to payoff the debt";
char *str1 = NULL;
char *str2 = NULL;
double value = 0.0;

str1 = ori_str;
str2 = strchr(str1, '$');
printf("$的位置是：\n");
printf("%d\n\n",(int)(str2 - str1+1));

value = atof(str2 + 1);
printf("double value:\n\n %.2f",value);


char *s="You will pay $687.71 every month for 15 years to payoff the debt";
char *l="years";
char *p;
p=strstr(s,l);
if(p)
    printf("\n%d\n",p-s+1);
else
    printf("NotFound!");

}

比如这段程序就是输出years15？