The random idiom I got was: > Idiom #120 Read integer from stdin > Read an integer value from the standard input into variable n int n[15]; fgets(n, 15, stdin); Really?
The random idiom I got was: > Idiom #137 Check if string contains only digits > Set boolean b to true if string s contains only characters in range '0'..'9', false otherwise. char b = 0; for (int i = 0; i = '0' && s[i] I appreciate the funny assignment-and-test-and-early-break in one (although I'd hardly say it's idiomatic), but I could do without the quadratic strlen().
Also, code like this should always be put inside a function that returns a value, not just written inline. Making it a function allows simpler and more understandable code too.
The funniest part is that it is not necessary to call strlen() at all! The whole thing can be written in a single pass over the string. Here is how I would code it in C:
int OnlyDigits( char str[] ) {
for( int i = 0; str[i] != '\0'; ++i ) {
if( str[i] '9' ) return 0;
}
return 1;
}