循环问题

#include  <stdio.h > 
#include  <math.h > 
main（) 
{ 
    float r2,r3,r4,rg,e,ig,result,uper,lint; 
    char c; 
    printf（"please input r2,and r3,and r4,and e,and rg（end with enter):"); 
    scanf（"%f%f%f%f%f",&r2,&r3,&r4,&e,&rg); 
    do 
    { 
        printf（"please input ig:"); 
        scanf（"%f",&ig); 
        result=（r2*r3*e-ig*（r2*r3*r4+rg*r2*r3+rg*r2*r4))/（e*r4+ig*（r2*r3+r3*r4+r4*r2+rg*r3+rg*r4)); 
        printf（"the result is:%f\n",result); 
        printf（"the 1/t is:%f\n",1/result); 
        printf（"the ln t is:%f\n",log（result)); 
        printf（" continue with y"); 

        fflush（stdin);
        
    }while（（c=getchar（))== 'y '); 
    
}