sscanf behaviour / return value

Question

I\'m a novice learning C and trying to understand the following code from an online lecture. It scans a string for an integer; if characters are encountered, the sscanf fail

Answer 1

Your sscanf(string, " %d %c") will return EOF, 0,1 or 2:

2: If your input matches the following
[Optional spaces][decimal digits*][Optional spaces][any character][extra ignored]

1: If your input failed above but matched the following
[Optional spaces][decimal digits*][Optional spaces][no more data]

[Correction]
0: If your input, after white-space and an optional sign, did not find a digit: examples: "z" or "-".

EOF: If input was empty "" or only white-space.

• The decimal digits may be preceded by a sign character + or -.