走过路过，瞧一瞧，看一看。

有任何问题可以来有大神免费解答

n = 多少 ??

这是书上的一道习题，贴出全部代码，有心者可以跑一下看
题目：编写函数 strend(s,t) 如果字符串t出现在字符串s的尾部，该函数返回1，否则返回0.
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#include <stdio.h>
int strlen(char *s){
int n;
/*while(*s != '\0'){
n++;
s++;
}
return n; */
for(n = 0; *s != '\0'; s++){
n++;
}
return n;
}
int strcmp(char *s,char *t){
for(;*s == *t; s++, t++)
if(*s == '\0')
return 0;
return *s - *t;
}
int strend(char *s,char *t){
int s_len,t_len;
s_len=strlen(s);
t_len=strlen(t);
int start,result;
result=0;
if(s_len>=t_len){
start=s_len-t_len;
s+=start;
if(0==strcmp(s,t)){
result=1;
}
}
return result;
}
int main(void){
char *s1 = "some really long string.";
printf("len=%d\n",strlen(s1));
char *s2 = "ng.";
char *s3 = "ng";
if(strend(s1, s2))
{ printf("The string (%s) has (%s) at the end.\n", s1, s2); }
else { printf("The string (%s) doesn't have (%s) at the end.\n", s1, s2); }
if(strend(s1, s3)) { printf("The string (%s) has (%s) at the end.\n", s1, s3); }
else { printf("The string (%s) doesn't have (%s) at the end.\n", s1, s3); }
return 0;
}