Comparing strings

We are now going to start working with strings. 
There are a couple of different nuances with strings that we need to learn about.
​

Scenario

A pangram is a sentence that uses every letter of the alphabet at least once. The most popular English pangram is "The quick brown fox jumps over the lazy dog." It contains 35 letters and each letter is used at least once. Write code to check whether a given string is a pangram or not. Try to write the shortest code possible. You can use the string class and arrays. Remember not to count spaces and other specialcharacters. At the end of this program you should print how many times each letter has been used. ​

Sample Code

#include <iostream>
#include <math.h>

using namespace std;


bool is_close(double a, double b, double tolerance){
     // Your code goes here
     return false;
}


int main(void) {

if (0.3 == 3 * 0.1) {
     cout << "The numbers are equal";
     }
​else {
     cout << "The numbers are not equal";
     }
     cout << endl;

if (is_close(0.3, 3 * 0.1, 0.00000001)) {
     cout << "The numbers are close enough";
     }
else {
     cout << "The numbers are not close enough";
     }
    cout << endl;

// this should work regardless of the argument order
if (is_close(3 * 0.1, 0.3, 0.00000001)) {
     cout << "The numbers are still close enough";
     }
else {
     cout << "The numbers are not close enough";
     }
     cout << endl;

if (is_close(3 * 0.1, 0.31, 0.00000001)) {
     cout << "The numbers are still close enough";
     }
else {
     cout << "The numbers are not close enough";
     }
     cout <<endl
​
return 0;
}

Sample Output

The numbers are not equal
The numbers are close enough
The numbers are still close enough
​The numbers are not close enough