C language array - string-CodePudding

Input two strings str1 and str2, judge whether str2 str1 substring, if yes, please delete the str1 substring str2 after part of the output (note: if the str1 contains multiple str2 substring, only will be deleted in the str1 the rightmost part of the output after a substring)

Novice c language, for arrays and strings don't quite understand this, for advice

CodePudding user response:

STRSTR function is to find any substring, calls to find the last clause!
For example

 int delstr (char * str1, char * str2) {
If (str1==NULL | | str2==NULL) return 0; 
Int len1=(int) strlen (str1), len2=(int) strlen (str2); 
If (len1 & lt; Len2) return 0; 
Else if (len2==0) return 1; 

P1=str1, char * * p2=str1;//the code above is normal data, can be ignored, start from here is the main code 
While ((p1=STRSTR (p1, str2))!=NULL) {//STRSTR couldn't find a substring the return value is NULL, or to find the position of the substring 
P1 p2=;//records to find the location of the 
P1 +=len2;//modify the next search start 
} 
If (p2==str1) return 0;//if the substring didn't find the return 
Strcpy (p2, p2 + len2); Starting from the last//find position, after the length of string to copy over 
* (str1 + len1 - len2)='\ 0';//modify the final string terminator 
return 1; 
} 

Int main (int arg c, const char * argv []) {
Char str1 []={" abcdabcdab "}; 
Char str2 []={" CD "}; 
Delstr (str1, str2); 
Printf (" % s \ n ", str1); 
return 0; 
}

CodePudding user response:

STRSTR function, the search string in another position, can't find the return NULL
Starting from the str1 last str2 long string such as comparison, continue to move forward one character at a time don't match, know, or reach the head so far
The problem now for a few days to have seen the same problems

Int delstr (char * str1, char * str2) {
If (str1==NULL | | str2==NULL) return 0;
Int len1=(int) strlen (str1), len2=(int) strlen (str2);
If (len1 & lt; Len2) return 0;
Else if (len2==0) return 1;

Char * p=str1 + len1 len2;//positioning to the str1 len2 last the length of the string
While (p & gt;=str1) {//not end
If (p==STRSTR (p, str2)) break;//from the back forward gradually find, if found will be the current pointer
P -;
}
If (p & lt; Str1) return 0;//if the substring didn't find the return

Strcpy (p, p + len2); Starting from the last//find position, after the length of string to copy over
* (str1 + len1 - len2)='\ 0';//modify the final string terminator
return 1;
}

CodePudding user response:

reference 1st floor qybao response:

STRSTR function is to find any substring, constant calls to find the last clause!
For example

 int delstr (char * str1, char * str2) {
If (str1==NULL | | str2==NULL) return 0; 
Int len1=(int) strlen (str1), len2=(int) strlen (str2); 
If (len1 & lt; Len2) return 0; 
Else if (len2==0) return 1; 

P1=str1, char * * p2=str1;//the code above is normal data, can be ignored, start from here is the main code 
While ((p1=STRSTR (p1, str2))!=NULL) {//STRSTR couldn't find a substring the return value is NULL, or to find the position of the substring 
P1 p2=;//records to find the location of the 
P1 +=len2;//modify the next search start 
} 
If (p2==str1) return 0;//if the substring didn't find the return 
Strcpy (p2, p2 + len2); Starting from the last//find position, after the length of string to copy over 
* (str1 + len1 - len2)='\ 0';//modify the final string terminator 
return 1; 
} 

Int main (int arg c, const char * argv []) {
Char str1 []={" abcdabcdab "}; 
Char str2 []={" CD "}; 
Delstr (str1, str2); 
Printf (" % s \ n ", str1); 
return 0; 
}

It is no good, such as in c1c1c c1c, the above code will find

CodePudding user response:

Fun

reference 3 floor response:

it is no good, such as in c1c1c c1c, the above code will find

Indeed, ignore the substring overlap and should be a pointer to a displacement of a judgment

 int delstr (char * str1, char * str2) {
If (str1==NULL | | str2==NULL) return 0; 
Int len1=(int) strlen (str1), len2=(int) strlen (str2); 
If (len1 & lt; Len2) return 0; 
Else if (len2==0) return 1; 
If (STRSTR (str1, str2)==NULL) return 0;//modify - "if you can't find substring returned directly 

P1=str1, char * * p2=str1; 
While (* p1!='\ 0') {//modify 
If (memcmp (p1, str2, len2)==0) {//modify -- "directly comparing memory 
P1 p2=; 
} 
P1 + +;//a displacement of a 
If (strlen (p1) & lt; Len2) break; 
} 

Strcpy (p2, p2 + len2); 
* (str1 + len1 - len2)='\ 0'; 
return 1; 
} 

Int main (int arg c, const char * argv []) {
Char str1 []={" c1c1c "}; 
Char str2 []={" c1c "}; 
Delstr (str1, str2); 
Printf (" % s \ n ", str1); 
return 0; 
}

CodePudding user response:

The while loop change
for (int i=0; I + len2 & lt;=len1; I++, p1 + +) {
If (memcmp (p1, str2, len2)==0) {
P1 p2=;
}
}

CodePudding user response:

reference 5 floor qybao reply:

while loop change
for (int i=0; I + len2 & lt;=len1; I++, p1 + +) {
If (memcmp (p1, str2, len2)==0) {
P1 p2=;
}
}

While ((p1=STRSTR (p1, str2))!=NULL) {//STRSTR couldn't find a substring the return value is NULL, or to find the position of the substring
P1 p2=;//records to find the location of the
P1 +=1;//this move a bit at a time ok also 1
}

CodePudding user response:

Fun

reference 2 floor response:

STRSTR function, the location of the search string in the midst of another, can't find the return NULL
Starting from the str1 last str2 long string such as comparison, continue to move forward one character at a time don't match, know, or reach the head so far
The problem now for a few days to have seen the same problems

Int delstr (char * str1, char * str2) {
If (str1==NULL | | str2==NULL) return 0;
Int len1=(int) strlen (str1), len2=(int) strlen (str2);
If (len1 & lt; Len2) return 0;
Else if (len2==0) return 1;

Char * p=str1 + len1 len2; nullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnull