Check if input is float else stop

Question

scanf(\"%f\", &num);

I have to check if thats a valid float variable and stop executing if it has symbols like @ or !

Answer 1

Using the %f specifier in scanf won't scan anything else, if no float is specified, nothing will be read. You should check the return value of scanf.

There are a few defined return values:

EOF = -1
invalid input = 0
valid = >0