Write a program with three functions: upper, lower, and flip. Each function should accept a C-string as an argument. The upper function should step through all the characters in the string, converting each to uppercase. The lower function, should step through all the characters in the string converting, each to lowercase. The flip steps through the string, testing each character to determine whether it is upper or lowercase. If upper, it should convert to lower. If lower, it should convert to uppe

explanation #include <iostream>#include <cstring>#include <string>using namespace std;//function prototypevoid reverse(char *);void lower(char *);void upper(char *);int main(){    //declare char array to hold user string    char inputString[101];    //prompt user to enter string then read    cout << "Please enter a string (max length 100 characters):\n";    cin.getline(inputString, 101);    //call functions in order that is specified    reverse(inputString);    lower(inputString);    upper(inputString);    //return 0 to mark successful termination    return 0;}void reverse(char *input){    cout << "String with reversed case: \n";    //loop through each char using for loop    //that goes from first char until last    for(int counter = 0; counter < strlen(input)-1; counter++){        //if it is uppercase, print lowercase equivalent        if(isupper(input[counter]))            cout << (char) tolower(input[counter]);        //if it is lowercase, print uppercase equivalent        else            cout << (char) toupper(input[counter]);    }    //print newline    cout << endl;}void lower(char *input){    cout << "String with lowered case: \n";    //loop through each char using for loop    //that goes from first char until last    for(int counter = 0; counter < strlen(input)-1; counter++){        //if it is uppercase, print lowercase equivalent        if(isupper(input[counter]))            cout << (char) tolower(input[counter]);        //if it is lowercase, print as is        else            cout << input[counter];    }    //print newline    cout << endl;}void upper(char *input){    cout << "String with uppered case: \n";    //loop through each char using for loop    //that goes from first char until last    for(int counter = 0; counter < strlen(input)-1; counter++){        //if it is lowercase, print uppercase equivalent        if(islower(input[counter]))            cout << (char) toupper(input[counter]);        //if it is uppercase, print as is        else            cout << input[counter];    }    //print newline    cout << endl;}hope this help