很多人在使用C格式说明符时遇到很多问题。他们大多数都不知道：
我想用表格显示这些，并通过说明为每个格式说明符提供一个示例。
Format specifier Description Type range Uses
%c Character char -128 to 128 Use to output single character
%c Character unsigned char 0 to 255 Use to output single character
%s String char * - Use to output any range of strings
示例
#include <stdio.h>
int main()
{
char letter1 = 'a';
unsigned char letter2 = 'a';
char *words1 = "Hello World!";
char words2[] = "Hello Guys!";
printf("letter 1 = %c", letter1); //Output only one character
printf("\nletter 2 = %c\n", letter2);
printf("\n%s", words1); //Output any range of strings
printf("\n%s", words2);
letter1 = 255;
letter2 = 255;
printf("\n\nchar = %d\n", letter1); //Diferrence between char and unsigned char
printf("Unsigned char = %d\n", letter2);
return 0;
}
输出
letter 1 = a
letter 2 = a
Hello World!
Hello Guys!
char = -1
Unsigned char = 255
Format specifier Description Type range(Uses)
%hd Integer short int -32,768 to 32,767
%hu " unsigned short int 0 to 65,535
示例
#include <stdio.h>
int main()
{
short int min1 = -32768;
short int max1 = 32767;
unsigned short int min2 = 0;
unsigned short int max2 = 65535;
printf("Minimum value of short int = %hd", min1);
printf("\nMaximum value of short int = %hd", max1);
printf("\n\nMinimum value of unsigned short int = %hu", min2);
printf("\nMaximum value of unsigned short int = %hu", max2);
return 0;
}
输出
Minimum value of short int = -32768
Maximum value of short int = 32767
Minimum value of unsigned short int = 0
Maximum value of unsigned short int = 65535
Format specifier Description Type range Uses
%d Integer int -2,147,483,648 to 2,147,483,647 Can take integers as decimals
%u " unsigned int 0 to 4,294,967,295 Output only positive numbers
%i " unsigned int -2,147,483,648 to 2,147,483,647 Can take integers as decimals,
hexadecimals and octals type.
示例
#include <stdio.h>
int main()
{
int min1 = -2147483648;
int max1 = 2147483647;
unsigned int min2 = 0;
unsigned int max2 = 4294967295;
unsigned int min3 = -2147483648;
unsigned int max3 = 2147483647;
unsigned int decimal = 12;
unsigned int octal = 012;
unsigned int hexadecimal = 0X12;
printf("Minimum value of int = %d", min1);
printf("\nMaximum value of int = %d", max1);
printf("\n\nMinimum value of unsigned int(u) = %u", min2);
printf("\nMaximum value of unsigned int(u) = %u", max2);
printf("\n\nMinimum value of unsigned int(i) = %i", min3);
printf("\nMaximum value of unsigned int(i) = %i", max3);
printf("\n\n12 in decimal format = %i", decimal);
printf("\n012 in octal format = %i", octal);
printf("\n0X12 in hexadecimal format = %i", hexadecimal);
return 0;
}
输出
Minimum value of int = -2147483648
Maximum value of int = 2147483647
Minimum value of unsigned int(u) = 0
Maximum value of unsigned int(u) = 4294967295
Minimum value of unsigned int(i) = -2147483648
Maximum value of unsigned int(i) = 2147483647
12 in decimal format = 12
012 in octal format = 10
0X12 in hexadecimal format = 18
Format specifier Description Type range(Uses)
%ld or %li Integer long int -2,147,483,648 to 2,147,483,647
%lu " unsigned long int 0 to 4,294,967,295
%lld or %lli " long long int -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807(-(2^63) to (2^63)-1)
%llu " unsigned long long int 0 to 18,446,744,073,709,551,615
示例
#include <stdio.h>
int main()
{
long int min1 = -2147483648;
long int max1 = 2147483647;
unsigned long int min2 = 0;
unsigned long int max2 = 4294967295;
long long int min3 = -9223372036854775808; // 2^63
long long int max3 = 9223372036854775807; // 2^63 - 1
unsigned long long int min4 = 0;
unsigned long long int max4 = 18446744073709551615;
printf("Minimum value of long int(ld) = %ld", min1);
printf("\nMaximum value of long int(ld) = %ld", max1);
printf("\n\nMinimum value of long int(li) = %li", min1);
printf("\nMaximum value of long int(li) = %li", max1);
printf("\n\nMinimum value of unsigned long int(lu) = %lu", min2);
printf("\nMaximum value of unsigned long int(lu) = %lu", max2);
printf("\n\nMinimum value of long long int(lld) = %lld", min3);
printf("\nMaximum value of long long int(lld) = %lld", max3);
printf("\n\nMinimum value of long long int(lli) = %lli", min3);
printf("\nMaximum value of long long int(lli) = %lli", max3);
printf("\n\nMinimum value of unsigned long long int(llu) = %llu", min4);
printf("\nMaximum value of unsigned long long int(llu) = %llu", max4);
return 0;
}
输出
Minimum value of long int(ld) = -2147483648
Maximum value of long int(ld) = 2147483647
Minimum value of long int(li) = -2147483648
Maximum value of long int(li) = 2147483647
Minimum value of unsigned long int(lu) = 0
Maximum value of unsigned long int(lu) = 4294967295
Minimum value of long long int(lld) = -9223372036854775808
Maximum value of long long int(lld) = 9223372036854775807
Minimum value of long long int(lli) = -9223372036854775808
Maximum value of long long int(lli) = 9223372036854775807
Minimum value of unsigned long long int(llu) = 0
Maximum value of unsigned long long int(llu) = 18446744073709551615
Format specifier Description Type Range Uses
%f Float float 1.2E-38 to 3.4E+38 Use when number has 6 decimal places
%lf Double double 2.3E-308 to 1.7E+308 Use when number has 15 decimal places
%Lf Long Double long Double 3.4E-4932 to 1.1E+4932 Use when number has 19 decimal places
%e or %E Float, Double float, double Scientific notation of float values
%g or %G Float, Double float, double Scientific notation of float values
Accept integers and float double also
示例
#include <stdio.h>
int main()
{
float number1 = 5.12;
double number2 = 5;
long double number3 = 5;
printf("Float number is(f) = %f", number1);
printf("\nDouble number is(lf) = %lf", number2);
printf("\nLong Double number is(Lf) = %Lf", number3);
printf("\n\nFloat number is(e) = %e", number1);
printf("\nDouble number is(e) = %e", number2);
printf("\n\nFloat number is(E) = %E", number1);
printf("\nDouble number is(E) = %E", number2);
printf("\n\nFloat number is(g) = %g", number1); //Support for both integers and floats, doubles
printf("\nDouble number is(g) = %g", number2);
printf("\n\nFloat number is(G) = %G", number1); //Support for both integers and floats, doubles
printf("\nDouble number is(G) = %G", number2);
return 0;
}
输出
Float number is(f) = 5.120000
Double number is(lf) = 5.000000
Long Double number is(Lf) = 5.000000
Float number is(e) = 5.120000e+00
Double number is(e) = 5.000000e+00
Float number is(E) = 5.120000E+00
Double number is(E) = 5.000000E+00
Float number is(g) = 5.12
Double number is(g) = 5
Float number is(G) = 5.12
Double number is(G) = 5
Format specifier Description Type Uses
%o Integer short int, unsigned short int Octal representation of Integer.
int, unsigned int, long int
%x or %X Integer short int, unsigned short int Hexadecimal representation of an Integer.
int, unsigned int, long int
%p Void * void * Use to get address of pointer or any other variable
Address of pointer to void void *
%n - - Prints nothing.It cause printf() to load the variable
pointed by corresponding argument. The loading is done with
a value which is equal to the number of characters printed
by printf() before the occurrence of %n.
%% - - Prints % character.
示例
#include <stdio.h>
int main()
{
int num1 = 65;
int num2 = 67;
int num3 = 15;
int* ptr =&num3;
int num4;
int num5 = 20;
printf("Octal representation of 65 = %o", num1);
printf("\nOctal representation of 67 = %o", num2);
printf("\n\nHexadecimal representation of 15(x) = %x", num3);
printf("\nHexadecimal representation of 15(X) = %X", num3);
printf("\n\nAddress of pointer = %p",ptr);
printf("\n\nThe value of %nnum4 and %nnum5 is = ", &num4, &num5); //Uses of %n
printf("%d %d", num4, num5);
printf("\n\nI got 50%% discount when I was shopping"); //Uses of %%
return 0;
}
输出
Octal representation of 65 = 101
Octal representation of 67 = 103
Hexadecimal representation of 15(x) = f
Hexadecimal representation of 15(X) = F
Address of pointer = 0x7ffe402adda4
The value of num4 and num5 is = 15 24
I got 50% discount when I was shopping