main()                                                          
   {                                                               
       int m;                                                      
       float x, sum, average;                                      
                                                               
       printf("This program computes the average of a          
                    set of numbers\n");                        
       printf("Enter values one after another\n");                 
       printf("Enter a NEGATIVE number at the end.\n\n");             
       sum = 0;                                                
       for (m = 1 ; m < = 1000 ; ++m)                               
       {                                                           
           scanf("%f", &x);                                        
           if (x < 0)                                              
              break;                                               
           sum += x ;                                          
       }   
                                                        
       average = sum/(float)(m-1);                             
       printf("\n");                                           
       printf("Number of values = %d\n", m-1);                     
       printf("Sum              = %f\n", sum);                 
       printf("Average          = %f\n", average);             
   }                                                               
                                                               
Output                                                      
                                                               
   This program computes the average of a set of numbers       
   Enter values one after another                              
   Enter a NEGATIVE number at the end.                         
                                                               
   21  23  24  22  26  22  -1                                  
                                                               
   Number of values = 6                                        
   Sum              = 138.000000                               
   Average          = 23.000000