using C copy a 1D char array into 2D char array

I am trying to copy a 1D array of Strings into a 2D array of strings in C.

I was able to achieve this with integer
enter image description here

//Here is what I tried for integers.
        int main() 
    { 
        int arr[3][3];
        int arr2[9]={1,2,3,4,5,6,7,8,9}; 
    
        int i,j,k=0; 
    
        for(i=0; i<3;i++){
            for(j=0; j<3;i++){
              arr[j][i] = arr2[i];
                //rintf("%d\n",arr2[i]);
            }
            
        }
    
     for(i=0; i<3; i++) { 
        for(j=0; j<3; j++) 
          printf("%2d  ", arr[j][i]); 
        printf("\n"); 
      } 
    
        return 0; 
    } 

I changed my data to char and I tried to run the same code I got a segmentation error.
Here is what I have tried so far and it didnt work. error :Segmentation fault (core dumped)

 #include<stdio.h> 
#include<string.h> 
 
int main() 
{ 
    char *d[3][3];  // Destination array 

    char *s[9]={"orange","apple","table","chair","cable","TV", "124","HI"};   // Source 1 Day array

    int i,j,k=0; 

    for(i=0; i<3;i++){
        for(j=0; j<3;i++){
            
          strcpy(d[j][i], s[i]);
           
        }
            }

 for(i=0; i<3; i++) { 
    for(j=0; j<3; j++) 
      printf("%s  ", d[j][i]); 
    printf("\n"); 
  } 

    return 0; 
} 

I have made some adjustment and now it print some weird strings

#include<stdio.h> 
#include<string.h> 
 
int main() { 

    char d[3][3] ={0};  // Destination array 

    char s[9][8]={"orange","apple","table","chair","cable","TV", "124","HI"};   // Source 1 Day array

    int i,j,k=0; 
    
    for(i=0; i<3;i++){
        for(j=0; j<3;j++){

            d[j][i] = *s[i];
           
        }
            }
    
    for(i=0; i<3; i++) { 
        for(j=0; j<3; j++) 
            printf("%s  ", &d[j][i]); 
            printf("\n"); 
    } 

    return 0; 
} 

enter image description here

>Solution :

This for loop

    for(i=0; i<3;i++){
        for(j=0; j<3;i++){
          arr[j][i] = arr2[i];
            //rintf("%d\n",arr2[i]);
        }
        
    }

is incorrect. In the inner loop there are used the same elements arr2[i] where i is changed from 0 to 2 inclusively.

You need to write

    for(i=0; i<3;i++){
        for(j=0; j<3;i++){
          arr[j][i] = arr2[ 3 * i + j];
        }
    }

Another way to write loops is the following

    for ( i = 0; i < 9; i++ )
    {
        arr[i / 3][i % 3] = arr2[i];
    }

As for arrays of pointers of the type char * then the nested loops will look similarly

for(i=0; i<3;i++){
    for(j=0; j<3;i++){
        
      d[i][j] = s[ 3 * i + j];
       
    }
}

provided that the array s is declared like

char * s[9]={"orange","apple","table","chair","cable","TV", "124","HI"};   

And to output the result array you need to write

 for(i=0; i<3; i++) { 
    for(j=0; j<3; j++) 
      printf("%s  ", d[i][i]);
                     ^^^^^^^ 
    printf("\n"); 
  } 

As for your last program then it can look like

#include<stdio.h> 
#include<string.h> 
 
int main( void ) 
{ 

    char d[3][3][8] ={0};  // Destination array 

    char s[9][8]={"orange","apple","table","chair","cable","TV", "124","HI"};   // Source 1 Day array

    for( size_t i = 0; i < 3; i++ )
    {
        for ( size_t j = 0; j < 3;j++ )
        {
            strcpy( d[j][i], s[3 * i + j] );
           
        }
    }
    
    for ( size_t i = 0; i < 3; i++ ) 
    { 
        for ( size_t j = 0; j < 3; j++ )
        { 
            printf( "%s  ", d[i][j] ); 
        }
        putchar( '\n' ); 
    } 

    return 0; 
} 

Leave a Reply