Usage details for printf (in Xcode development environment)

Use of printf

1. Direct output of a text output result

printf ("Hello, world!\n"); "Hello, world!."

2. output int type data

int num=100;

printf ("%i\n", num); "Up" general output

printf ("%2i\n", num); " the"

printf ("%4i\n", num); Note that there are spaces at the beginning .

printf ("%-4i\n", num); Note that there are spaces at the end of the "

printf ("%04i\n", num); "0100"

Description

A the first letter of the INT data type Here I, indicating the output int type data

The 4 in front of B indicates the length of the output data and the space before the length is insufficient (by default)

The actual length of the C data is greater than the output length, whichever is true.

D to add a number before the output length, the length is padded at the end with a space

e If the output length is preceded by 0, indicating that the output length is insufficient in front of 0

3. Output Float type data

float floatvalue=10.0f;

printf ("%f\n", Floatvalue); "10.000000"

printf ("%.4f\n", Floatvalue); "10.0000"

Description

A f indicates output float type data

B. 4 indicates that decimal digits are reserved for four bits, followed by rounding

**c float data has a maximum of 6 decimal places and is inaccurate when the number of decimal places is greater than 6 o'clock

Usage details for printf (in Xcode development environment)