Common String Functions in ACM

1. String substitution

Syntax: replace (char Str[],char Key[],char swap[]);
Parameters:
Str[]:	Replace operation on this source string
Key[]:	The string to be replaced, cannot be an empty string
Swap[]:	The replacement string, which can be an empty string, is an empty string representing the deletion of key[in the source character]
return value:	Null
Attention:
	Default str[] length less than 1000, if no, reset the TMP size setting
	Need string.h
SOURCE program:
	void replace (char Str[],char Key[],char swap[]) { int l1,l2,l3,i,j,flag; Char tmp[1000]; L1=strlen (str); L2=strlen (key); L3=strlen (swap); for (i=0;i<=l1-l2;i++) { flag=1; for (j=0;j<l2;j++) if (Str[i+j]!=key[j]) { flag=0;break; } if (flag) { strcpy (TMP,STR); strcpy (&tmp[i],swap); strcpy (&tmp[i+l3],&str[i+l2]); strcpy (str,tmp); i+=l3-1; L1=strlen (str);}}}

2. String Lookup

Syntax: Result=strfind (char Str[],char key[]);
Parameters:
Str[]:	Find operations on this source string
Key[]:	The string to be searched for cannot be empty
return value:	If the lookup succeeds, returns the position where key first appears in STR, otherwise returns-1
Attention:
	Need string.h
SOURCE program:
	int Strfind (char str[],char key[]) { int l1,l2,i,j,flag; L1=strlen (str); L2=strlen (key); for (i=0;i<=l1-l2;i++) { flag=1; for (j=0;j<l2;j++) if (Str[i+j]!=key[j]) {flag=0;break;} if (flag) return i; } return-1; }

3. String interception

Syntax: Mid (char str[],int start,int Len,char strback[])
Parameters:
Str[]:	The target string for the operation
Start	Starts with the beginning of the first string and intercepts the Len-length characters
Len:	Starts with the beginning of the first string and intercepts the Len-length characters
Strback[]:	truncated to the character
return value:	0: Out of string length, intercept failed; 1: Intercept Successful
Attention:
	Need string.h
SOURCE program:
	int mid (char str[],int start,int len,char strback[]) { int l,i,k=0; L=strlen (str); if (start+len>l) return 0; for (i=start;i<start+len;i++) strback[k++]=str[i]; strback[k]= ' + '; return 1; }

4. String reversal function

Char *strrev (char string[])//string inversion function

    {
        char *start=string;
        char *left=string;
        char ch;
        while (*string + +);
        string-=2;
        while (left<string)
        {
                ch=*left;
                *left++=*string;
                *string--=ch;
        }
        return (start);