#include <iostream>
using namespace std;
int main()
{   int BSR;
    int HighBSR=0 , LowBSR=0 , NormalBSR=0;
    int patients=0,sum =0;
    int count=0;
    while(patients != -1)}{{
        ( BSR ==120 )//HighBSR+=patients;
        { else if ( BSR>70 && BSR<120 )//NormalBSR+=patients;
    else ( BSR<=70 )//LowBSR+=patients;}
    ; count++;
    cout<<"The Number Of All Patients is:"<<patients;
    cout<<"The Number Of Patients With High BSR is:"<<HighBSR;
    cout<<"The Number Of Patients With Normal BSR is:"<<NormalBSR;
    cout<<"The Number Of Patients With Low BSR is:"<<LowBSR;
    float percentage;
    cout<<"The Percentage Of High BSR is:"<<percentage;
    return 0;

dunno what is the error
i've tried all ways
but i didn't find a solution

You have a close curly brace after your while statement that shouldn't be there. Please re post your code with code tags to make it easier to read. Also you might want to look up proper indenting and code formatting styles.