Thread: how to properly indent and format a source code?

Hello.

I want to learn how to indent and format properly my source codes. I have found this online:

https://en.wikipedia.org/wiki/Indent_style
GNU Coding Standards: Formatting

Here is a source code that I wrote where I was criticized that it is not correctly formated:

why this code is not working? i wanted to multiply a matrix by itself

Code:

#include <stdio.h>
  
int main()
{
    int i,j;
    int array1[3][3]= {{0,0,0},{0,12,36},{0,32,56}} ;
    int sqr[3][3];
 
    /* multiplication part */
    for(i=0;i<3;i++)
    {
           for(j=0;j<3;j++){
                              sqr[i][j]=array1[i][0]*array1[0][j]+array1[i][1]*array1[1][j]+array1[i][2]*array1[2][j];
                           }
    }
 
 
 
    /* here is the printing part */
    for(i=0;i<3;i++)
    {
        for(j=0;j<3;j++){
                        printf("%d\t",sqr[i][j]);
                        }
        printf("\n");
    }
    return 0;
}

1) What does it mean to properly indent a code? >> I think that this is pretty clearly explained in the wikipedia article and I think that I already do that right, even in the example

2) What does it mean to properly indent a code? >> Does it mean two empty lines between code? What more?

Thank you.

A corrected version:

Code:

#include <stdio.h>
  
int main()
{
    int i,j;
    int array1[3][3]= {{0,0,0},{0,12,36},{0,32,56}} ;
    int sqr[3][3];
 

    /* multiplication part */
    for(i=0;i<3;i++)
    {
        for(j=0;j<3;j++){
                           sqr[i][j]=array1[i][0]*array1[0][j]+array1[i][1]*array1[1][j]+array1[i][2]*array1[2][j];
                        }
    }


    /* here is the printing part */
    for(i=0;i<3;i++)
    {
        for(j=0;j<3;j++){
                        printf("%d\t",sqr[i][j]);
                        }
        printf("\n");
    }


    return 0;
}

Look at the indent style wiki page you posted.

Tell me which indent style your code matches up with..

I think that the one I used is the Allman style.

https://en.wikipedia.org/wiki/Indent_style#Allman_style

I see it now. For the code more on the right I used the Whitesmiths_style..

https://en.wikipedia.org/wiki/Indent...tesmiths_style

EDIT: Here it is all just in Allman indent style:

Code:

#include <stdio.h>
   
int main()
{
    int i,j;
    int array1[3][3]={{0,0,0},{0,12,36},{0,32,56}};
    int sqr[3][3];
  
 
    /* multiplication part */
    for(i=0;i<3;i++)
    {
        for(j=0;j<3;j++)
        {
            sqr[i][j]=array1[i][0]*array1[0][j]+array1[i][1]*array1[1][j]+array1[i][2]*array1[2][j];
        }
    }
 
 
    /* here is the printing part */
    for(i=0;i<3;i++)
    {
        for(j=0;j<3;j++)
        {
            printf("%d\t",sqr[i][j]);
        }
        printf("\n");
    }
 
 
    return 0;
}

Is it better to stick to one indent style? I suppose yes.

How about the formatting?

Post number three of this thread contains a corrected version.

So the formatting is about number of spaces between a code starts on a line and between spaces between lines of different type of code?

Thank you all.

Here is the current version:

Code:

#include <stdio.h>

int main()
{
    int i,j;
    int array1[3][3] = { { 0,  0,  0 },
                         { 0, 12, 36 },
                         { 0, 32, 56 } };
    int sqr[3][3];


    /* multiplication part */
    for(i=0;i<3;i++)
    {
        for(j=0;j<3;j++)
        {
            sqr[i][j]=array1[i][0]*array1[0][j]
                     +array1[i][1]*array1[1][j]
                     +array1[i][2]*array1[2][j];
        }
    }


    /* here is the printing part */
    for(i=0;i<3;i++)
    {
        for(j=0;j<3;j++)
        {
            printf("%d\t",sqr[i][j]);
        }
        printf("\n");
    }


    return 0;
}

How to recognize a case for using spaces and for using tabs? In my text editor one tab equals eight spaces.

I have a better experience of using spaces, because with tabs in different editors the text is just somewhere else (more on the right or left). Maybe that in different editors one tab equals to different number of spaces.

Originally Posted by nerio

How to recognize a case for using spaces and for using tabs? In my text editor one tab equals eight spaces.

I prefer to just use spaces as I think it is easier to be consistent that way. If you do want to use tab characters, then make sure that they are used for the basic indentation only, not for pretty alignment of text.