STL Interview Question:

Write a program in C++ returning starting locations of a substring using pointers?

Submitted by: Administrator

#include<stdio.h>
#include<iostream.h>

int main()
{
char* mystrstr(char*,char*);
char str1[20];
char str2[10];
cout<<"n Enter two stringst";
cin>>str1>>str2;
cout<<"nstr1 = "<<str1<<" str2 "<<str2 ;
char* c= mystrstr(str1,str2);
if(c!=NULL)
printf("nc = %sn",c);
return 0;
}

char* mystrstr(char* str1, char* str2)
{
char *cp = (char *) str1;
char *s1, *s2;

if ( !*str2 )
return((char *)str1);
while (*cp)
{
s1 = cp;
s2 = (char *) str2;
while ( *s1 && *s2 && !(*s1-*s2) )
{
s1++;
s2++;
}

if (!*s2)
{
printf("n string foundn");
return(cp);
}
cp++;
}
return(NULL);
}
Submitted by: Administrator