Write a program in c plus plus to accept the string and then take the starting and ending point from the user and display the sub string through function?

Answer 1

#include<iostream>

#include<sstream>

unsigned input_num (std::string prompt, unsigned min, unsigned max)

{

unsigned num = 0;

while (1)

{

std::cout << prompt << " (range " << min << " - " << max << "): ";

std::string input = "";

std::getline (std::cin, input);

std::stringstream ss (input);

if (ss >> num)

{

if (num >= min && num <= max)

break;

else if (num<min)

std::cout << "Index must be greater than or equal to " << min << std::endl;

else

std::cout << "Index must be less than or equal to " << max << std::endl;

}

else

std::cout << "Invalid input." << std::endl;

}

return (num);

}

void print_substring (std::string input, unsigned left, unsigned right)

{

std::cout << input.substr (left, right - left + 1) << std::endl;

}

int main()

{

std::cout << "Input string:\t";

std::string input = "";

std::getline (std::cin, input);

unsigned left = input_num ("Enter the start index of the substring", 0, input.size()-1);

unsigned right = input_num ("Enter the end index of the substring", left+1, input.size()-1);

print_substring (input, left, right);

}