formatted output

hey, could u tell me what exactly this line means?
I need to print on the console telephone #s. How to understand the 3.3 4.4?Is there a better function that I can use? Can this be achieved with printf?

cprintf("%3.3s-%2.2s-%4.4s", student->SSN, &student->SSN[3], &student->SSN[5]);

Code:

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    "%3.3s

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The .3 has no effect here because it's used with "s" which is a string. The ".3" is supposed to be used with floating point (or double) values, not integers, strings, or characters.

Quzah.

Quzah, you're wrong, you can use this for strings too, look:

Code:

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#include <stdio.h>
#include <stdlib.h>

int main( void )
{
    char *test = "What's the result?";
   
    printf( "%2.4s\n", test );
    return 0;
}

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This have effect, and it'll print "What".

Years ago I created the following program to display all the different permutations of string formats for a printf statement.

Code:

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#include <stdio.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];
               
main(int argc, char *argv[])
{
    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");
}

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The output specifies a short string of 6 characters and a long one of 12 and how output is affected by X and Y values in a printf("%X.Ys"...) format designator.

Walt