수다닷컴

질문 제목 : string.h 헤더파일 없이 string관련 함수들을 구현하는 건데 문제가 있어요 ㅠㅠ위에 compare까지는 잘 되는데 concat 부분에서 말썽을 일으킵니다. 뭐가 문제인지 봐주세요 ㅠㅠ질문 내용 : #include stdio.h
#include stdlib.h

typedef struct {
char *str;
} string;string *createstring(char *str); // creates a new string with str
// use dynamic memory allocation (call malloc() twice)
string* copystring(string *str); //returns a copy of str
int comparestring(string *str1, string *str2); // compares two strings.
// if str1 precedes str2, return -1
// if str1 and str2 have the same content, return 0
// otherwise, return +1
string* concatenatestring(string *str1, string *str2); // returns a new string
// containing str1 + str2.
void deletestring(string *str); //deletes a string
// use free() to discard both str-str and str
char *getstring(string *str); // providedint getstrlen(char *str);int main()
{
string *str1 = null;
string *str2 = null;
string *str3 = null; str1 = createstring(abc);
str2 = createstring(123);
str3 = copystring(str1); printf(str1 = %s\n, getstring(str1));
printf(str2 = %s\n, getstring(str2));
printf(str3 = %s\n, getstring(str3)); printf(comparestring(str1, str2) = %d\n, comparestring(str1, str2));
printf(comparestring(str2, str1) = %d\n, comparestring(str2, str1));
printf(comparestring(str1, str3) = %d\n, comparestring(str1, str3)); deletestring(str3); str3 = concatenatestring(str1, str2); printf(concatenatestring(str1,str2) = %s\n, getstring(str3)); deletestring(str1);
deletestring(str2);
deletestring(str3); system(pause);
return 0;
}string *createstring(char *str) {
string *string = null;
int i; int length_of_string = getstrlen(str); string = (string*)malloc(sizeof(string)); string-str = (char*)malloc(length_of_string); for(i=0; i length_of_string; i++)
string-str[i]= str[i]; string-str[i] = 0; return string;
}string* copystring(string *str) {
int length = getstrlen(str-str); char* temp = (char*)malloc(length+1); int i; for(i=0; i length; i++)
temp[i] = str-str[i];

temp[i] = 0; str-str = temp; return str;
}

char* getstring(string *str)
{
return str-str;
}int comparestring(string *str1, string *str2) { int length1 = getstrlen(str1-str);
int length2 = getstrlen(str2-str);

int minlen = (length1 = length2 ? length1 : length2); int i = 0;
for(i = 0; i minlen; i++){
if(str1-str[i] str2-str[i])
return 1;
else if(str1-str[i] str2-str[i])
return - 1;
} if(length1 minlen)
return 1;
else if(length2 minlen)
return -1;
else
return 0;
}

string* concatenatestring(string *str1, string *str2) {

int len1 = getstrlen(str1-str); --------------------------여기를 읽어들일때 문제가 생깁니다 ㅜㅜ
int len2 = getstrlen(str2-str); string *temp = null;
int i;
int j; temp = (string*)malloc(sizeof(string)); temp-str = (char*)malloc(len1 + len2 + 1); for(i=0; i len1; i++)
temp-str[i] = str1-str[i]; for(j=0; j len2; i++, j++)
temp-str[i] = str2-str[j]; temp-str[i] = 0; return temp;
}void deletestring(string *str) {
if(str) {
if(str-str)
free(str-str);
free(str);
}
}

int getstrlen(char *str) {
int length = 0;
for(; str[length] !=0; length++); ----------------------이부분과 연계해서 그런것 같은데요
return length;

}다른 함수들에서는 getstrlen함수가 잘 작동하다가 유동 concat함수에서만 문제가 일어나네요....똑같이 썼는데 왜 유독 이곳에서만 문제가 나는지.....조언 부탁드립니다.함수의 return형태나 파라미터는 저대로 유지해야 합니다...ㅠ

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