Write a C++ program that reads three strings and prints the longest and smallest string.

#include<iostream.h>

#include<conio.h>

#include<string.h>

void main()
{
char str1[30], srt2[30], str3[30];

cout<<"\n Enter 3 strings /Words one-by-one(press enter each time) :";
gets(str1);
gets(str2);
gets(str3);

/* Find Longest String */
if(strcmp(str1, str2) > 0)
{
   if(strcmp(str1,str3)>0)
       cout <<"\n The Longest string is : " << str1;
  else
       cout <<"\n The Longest string is : " << str3;
}
else
{
if(strcmp(str2,str3)>0)
cout <<"\n The Longest string is : " << str2;
else
cout <<"\n The Longest string is : " << str3;
}


/* Find smallest String */


if(strcmp(str1, str2) < 0)

{
if(strcmp(str1,str3)<0)
cout <<"\n The Smallest string is : " << str1;
else
cout <<"\n The Smallest string is : " << str3;
}
else
{
if(strcmp(str2,str3)<0)
cout <<"\n The Smallest string is : " << str2;
else
cout <<"\n The Smallest string is : " << str3;
}

getch();
}

A menu driven program to enter a text(word / sentance) and convert it into Uppercase , Lowercase, Togglecase as per the user choice.

#include<iostream.h>

#include<conio.h>

#include<string.h>
{
char str[30], choice;
cout<<"\n Enter A String :";
cin.getline(str,30);
int t,i;


do{
cout<<"*************** MENU ********************\n";
cout<<"\n\n 1. UPPERCASE.";
cout<<"\n 2. LOWERCASE.";
cout<<"\n 3. TOGGLECASE.";


cout<<" Enter your choice (1-2-3)";
cin>>t;


switch(t)
{
case 1:
           for( i = 0; str[i] != '\0' ; i++)
                  str[i] = toupper(str[i]);
           cout<< "\n The output =" << str;


           break;
case 2:


          for( i = 0; str[i] != '\0' ; i++)
              str[i] = tolower(str[i]);
          cout<< "\n The output =" << str;


          break;
case 3:
          for( i = 0; str[i] != '\0' ; i++)


         {            
          
            if(isupper(str[i])
               str[i] = tolower(str[i]);
            if(islower(str[i])


               str[i] = toupper(str[i]);
            }
           cout<< "\n The output =" << str;
            break;
default:
             cout<<"\n Invalid choice.";
}


cout<<"\n Do you continue ?(Y/N)";
cin>>choice;
}while(toupper(choice)= ='Y');
}

A program that reads a string & a character . Each occurrence of the given character (regardless of its case) is converted to opposite case.

#include(iostream.h)

#include(conio.h)

#include(string.h)

void main()

{

char str[30], ch, ch1;

cout<<"\n Enter a String:";

cin.getline(str,30);

cout<<"\n Enter a character :";

cin>>ch;

for(int i =0; str[i]!='\0'; ++i)

{

if(toupper(ch) = = toupper(str[i]))

  {

    if(str[i]>='A' && str[i]<='Z')

         str[i] = str[i] + 32;

     else

         str[i] = str[i] - 32;

}

}

cout<<"\n The Converted String is  "<< str;

getch();

}