Flag Directives

The first optional field of the format specification is flags. A flag directive is a character that justifies output and prints signs, blanks, decimal points. More than one flag directive may appear in a format specification.

Flag Meaning Default
Left align the result within the given field width. Right align.
+Prefix the output value with a sign (+ or ) if the output value is of a signed type.Sign appears only for negative signed values ().
0If width is prefixed with 0, zeros are added until the minimum width is reached. If 0 and appear, the 0 is ignored. No padding.
blank (' ')Prefix the output value with a blank if the output value is signed and positive; the blank is ignored if both the blank and + flags appear.No blank appears.
#When used with the e, or f format the # flag forces the output value to contain a decimal point in all cases. Decimal point appears only if digits follow it.
 When used with the g format, the # flag forces the output value to contain a decimal point in all cases and prevents the truncation of trailing zeros.Decimal point appears only if digits follow it. Trailing zeros are truncated.