Using the for loop

I am programming this test commentor and I am trying to get it to restart again but I can't figure it out.

Code:

#include <iostream>

using namespace std;

int main()
{
    int percentage, i;
    
    cout<<"Input your test percentage: ";
    cin>>percentage;
    
    cin.ignore();
    
    if (percentage<50){
                       cout<<"You failed. Study harder.\n";
                       }
    else if (percentage<60){
                            cout<<"You just passed. Study harder.\n";
                            }
    else if (percentage<70){
                            cout<<"You didn't do very well.\n";
                            }
    else if (percentage<80){
                            cout<<"You did quite well.\n";
                            }
    else if (percentage<90){
                            cout<<"You did excellent.\n";
                            }
    else if (percentage<100){
                            cout<<"You did very well.\n";
                            }
    else if (percentage>100){
                            cout<<"Who marked your test?\n";
                            }
    else if (percentage==100){
                            cout<<"You did perfect.\n";
                             }
    cin.get();
}

What do I put in and where?

Code:

while ( someCondition ) {
  // the stuff you want to repeat
}

A for loop is generaly used when you have a set number of times the loop should be executed. (There are "tricks" you can use on them but that's another discusion)

A while loop is generaly used to execute as long as a condtion is true, a do while loop is the same as a while loop however it will execute at least once.

The syntex for a for loop is

for (variable initialization; conditional; variable increment) // the varable initialization is normaly an int.

Code:

for example for ( int i =0; i<Max_Percents; i++)
{
   the code you want to repeat
}

if you want to the user to enter data, indefinitly you have two options.

1. You can have a Sentinel- Controlled Loop, which has the user enter a unique value to end the loop

Code:

do
{
 your code
}while (input != sentinal);

2. You can put your input into a while statment, to end the loop you would press cntl+d. This is more benificial for reading from files, then user input though

ex:
while (cin>>percentage)

I just had to, i modified the code to the only way i know how to repeat a program,

Code:

#include <iostream>

using namespace std;

int main()
{
    int percentage, i, x;
    x=1;
    
    while(x==1)
    {
	
    cout<<endl;
    
    cout<<"Input your test percentage: ";
    cin>>percentage;
    
    cin.ignore();
    
    if (percentage<50){
                       cout<<"You failed. Study harder.\n";
                       }
    else if (percentage<60){
                            cout<<"You just passed. Study harder.\n";
                            }
    else if (percentage<70){
                            cout<<"You didn't do very well.\n";
                            }
    else if (percentage<80){
                            cout<<"You did quite well.\n";
                            }
    else if (percentage<90){
                            cout<<"You did excellent.\n";
                            }
    else if (percentage<100){
                            cout<<"You did very well.\n";
                            }
    else if (percentage>100){
                            cout<<"Who marked your test?\n";
                            }
    else if (percentage==100){
                            cout<<"You did perfect.\n";
                             }
    cout<<"\n \n \n To try again press 1, or press any key to exit!\n";
    cin>>x;
    cin.ignore();
	}
    
}

now i am sure there is another more "Clean" way of doing it, if so could anybody please explain?

And would it not be better to use something like

Code:

else if(percentage<90&&percentage>79){

Just askin as thats how i would do it

First things first: you have to learn to indent things properly. Do a google search, and examine some sample code.

And would it not be better to use something like

Code:

else if(percentage<90&&percentage>79){

You don't need to, because it's an else if, and the previous ifs have made sure that percentage is more than 79.

Look at this program.

Code:

#include <iostream>
#include <cctype>

using std::cout;
using std::cin;
using std::tolower;

int main(void) {
    char again;

    do {
        do_something();

        cout << "Do that again? ";
        cin >> again;
    } while(tolower(again) == 'y');
}

tolower() converts a letter to lowercase (there's also a toupper). These functions are in <cctype>.