My program skip getting input data? [duplicate]

Answer 1

Instead of scanf("%c", &buy);

1.use space before %c

scanf(" %c",&buy); //space before %c  
       ^ 

this skips reading of white space (including newlines).

2.or Use getchar(); before scanf("%c", &buy); statement

getchar(); //this hold the newline 
scanf("%c", &buy);

3.or use two times getchar();

getchar();
buy=getchar();     
//here getchar returns int , it would be better if you declare buy with integer type.

In GCC usage of fflush(stdin); is discouaraged. please avoid using it.