Adding a space before all format specifiers in scanf in C is crucial, especially when dealing with multiple consecutive inputs. This approach ensures that any leftover whitespace characters (such as spaces, tabs, or newlines) in the input buffer are skipped before reading new data. This is particularly important for format specifiers like %c, which would otherwise read these whitespace characters.

For example:

char ch; scanf(" %c", &ch); // The leading space ensures any previous newline or space is skipped.

Without the space, %c could inadvertently read a newline from the previous input.

However, adding a space after the format specifier (e.g., "%c ") is generally unnecessary and could lead to unexpected behavior, such as scanf waiting for a non-whitespace character to terminate the input.