printf formate string

[johndoe444]

Hi,

What is the significance of the following format specifiers:

%10s
%.10s
%-10s
%.15s
%-15s
%15.10s
%-15.10s

Thanks.

[Narue]

>What is the significance of the following format specifiers:
Relatively low, but they come in handy occasionally.

[WaltP]

>What is the significance of the following format specifiers:
Relatively low, but they come in handy occasionally.

:twisted: :twisted:

%10s    - Output a minimum of 10 chars, leading spaces
%.10s   - Output up to 10 characters
%-10s   - Output a minimum of 10 chars, trailing spaces
%.15s   - see above
%-15s   - see above
%15.10s  - output up to 10 chars with 5 leading spaces
%-15.10s - output up to 10 chars with 5 trailing spaces

You could have tested it out yourself, you know. Just write a program that tests them:

#include <stdio.h>
#include <string.h>
#define NEXTCOL 38

char *strs      = "ABCDEF";
char *strl      = "ABCDEFGHIJKL";
int   sizesingle= 9;
int   size[][2]= {   3,  3,   -3,  3,    3,  9,   -3,  9,
                     3, -3,    3, -9,   -3, -3,   -3, -9,
                     3, 15,    3,-15,   -3, 15,   -3,-15,
                     0,  0,
                     9,  3,   -9,  3,   -9,  9,   -9, -3,
                    -9, -9,   -9, 15,   -9, -15,   9,  9,
                     9, -9,    9, -3,    9,  15,   9,-15,
                     0,  0,
                    15,  3,   15,  9,   15, -3,   15, -9,
                    15, 15,   15,-15,  -15,  3,  -15,  9,
                   -15, -9,  -15, 15,  -15,-15,  -15, -3,
                    -1,  0
                  };
char buf[20];
                
int main()
{
    int  i = 0;
    int  j;
    
    j = printf("  Short -- %d chars <%s> ", strlen(strs), strs);
    while (j++ < NEXTCOL)  putchar(' ');
    printf("  Long -- %d chars <%s>  \n", strlen(strl), strl);
    printf("\n");
    
    j = sprintf(buf,"%*s", sizesingle, strs);
    j = printf("       %%%3ds (%2d)  <%s> ", sizesingle, j, buf);
    while (j++ < NEXTCOL)  putchar(' ');
    j = sprintf(buf,"%*s", sizesingle, strl);
    j = printf("       %%%3ds (%2d)  <%s> ", sizesingle, j, buf);
    printf("\n");
    
    j = sprintf(buf,"%*s", -sizesingle, strs);
    j = printf("       %%%3ds (%2d)  <%s> ", -sizesingle, j, buf);
    while (j++ < NEXTCOL)  putchar(' ');
    j = sprintf(buf,"%*s", -sizesingle, strl);
    j = printf("       %%%3ds (%2d)  <%s> ", -sizesingle, j, buf);
    printf("\n");
    
    j = sprintf(buf,"%.*s", sizesingle, strs);
    j = printf("       %%.%2ds (%2d)  <%s> ", sizesingle, j, buf);
    while (j++ < NEXTCOL)  putchar(' ');
    j = sprintf(buf,"%.*s", sizesingle, strl);
    j = printf("       %%.%2ds (%2d)  <%s> ", sizesingle, j, buf);
    printf("\n");
    
    j = sprintf(buf,"%.*s", -sizesingle, strs);
    j = printf("       %%.%2ds (%2d)  <%s> ", -sizesingle, j, buf);
    while (j++ < NEXTCOL)  putchar(' ');
    j = sprintf(buf,"%.*s", -sizesingle, strl);
    j = printf("       %%.%2ds (%2d)  <%s> ", -sizesingle, j, buf);
    printf("\n");
    
    printf("\n");

    while (size[i][0] != -1)
    {
    	if (size[i][0] != 0)
    	{ 
            j = sprintf(buf,"%*.*s", size[i][0], size[i][1], strs);
            j = printf("   %%%3d.%3ds (%2d)  <%s> ", size[i][0], size[i][1], j, buf);
            while (j++ < NEXTCOL)  putchar(' ');
            j = sprintf(buf,"%*.*s", size[i][0], size[i][1], strl);
            j = printf("   %%%3d.%3ds (%2d)  <%s> ", size[i][0], size[i][1], j, buf);
        }
        printf("\n");
        i++;
    }
    printf("done... \n");
    return 0;
}