#include <iostream>
#include <string>
using namespace std;
void main()
{
   char string[] = "The String to End All Strings!";
     cout<<"Mixed:\n"<<string<<endl;
       cout<<"Uper:\n"<<strupr(string)<<endl;
         char* lwr_str=strlwr(string);
           cout<<"Lower:\n"<<lwr_str<<endl;
}

//end

#include <iostream>
#include <string>
using namespace std;
void main(void)
{
   char ch='r';
   char string[] =
"The quick brown dog jumps over the lazy fox";
   char fmt1[] =
"         1         2         3         4         5";
   char fmt2[] =
"12345678901234567890123456789012345678901234567890";
   char* pdest;
   int result;
   cout<<"String to be searched: \n\t\t"<<string<<"\n";
    cout<<"\t\t"<<fmt1<<"\n\t\t"<<fmt2<<"\n\n";
     cout<<"Search char:\t"<<ch<<"\n";
/* Search forward. */
   pdest=strchr(string, ch);
    result=pdest - string + 1;
     if( pdest != NULL )
       cout<<"Result:\tfirst "<<ch
           <<" found at position "<<result<<"\n\n";
    else
       cout<<"Result:\t"<<ch<<" not found\n";
/* Search backward. */
   pdest=strrchr(string, ch);
    result=pdest - string + 1;
     if( pdest != NULL )
       cout<<"Result:\tfirst "<<ch
           <<" found at position "<<result<<"\n\n";
     else
       cout<<"Result:\t"<<ch<<" not found\n";
}

//end

#include <iostream>
#include <string>
using namespace std ;
int main()
{
    char str [16] = "how long am I ?";
    int len ;
    len = strlen(str) ;
    cout<<str<<" is "<<len<<" characters long\n";
  return 0;
}

//end

int strlen(const char *s)
{
    for(int i=0;s[i];++i);
    return i;
}
char *strrchr(const char *s,int c)
{
    long i;
    for(i=strlen(s)-1;i>=0 && s[i]!=(char)c;i--);
    if(i<0)
        return NULL;
    else
        return (char *)&s[i];
}

//end

char *strncpy(char *s,const char *t,unsigned n)
{
    for(unsigned i=0;i<n && t[i]!='\0';i++)
        s[i]=t[i];
    for(;i<n;i++)
        s[i]='\0';
    return s;
}

//end

char *strncat(char *s,const char *t,unsigned n)
{
    const char *p=t;
    unsigned i,j;
    i=j=0;
    while(s[i]!='\0')
        i++;
    while(j<n && (s[i++]=p[j++])!='\0');
    if(p[j-1]!='\0')
        s[i]='\0';
    return s;
}

//end

int strlen(const char *s)
{
    for(int i=0;s[i];++i);
    return i;
}
char *strchr(const char *s,int c)
{
    unsigned i;
    for(i=0;i<strlen(s) && s[i]!=(char)c;++i);
    if(i==strlen(s))
        return NULL;
    else
        return (char *)&s[i];
}

//end

char *strcat(char *s,const char *t)
{
    unsigned i,j;
    i=j=0;
    while(s[i]!='\0')
        i++;
    while((s[i++]=t[j++])!='\0');
    return s;
}

//end