Two Dimensional Array of Characters in C

Question

Help me to get out of this problem. I'm using GCC on ubuntu12.04. While I write this program to get 5 strings from keyboard n then print these strings on screen. Program is compiled but during execution it takes strings from keyboard but print only last string. The program which I have written is below:

void main()    
{  
    char names[10];  
    int i,j;

    for(i=0;i<5;i++)  
    {  
        printf(" Enter a name which you want to register\n");  
        scanf("%s",names);  
    }  
    for(i=0;i<5;i++)    
        printf(" the names you enter are %s\n", names);  

}

A two dimensional array is an array of arrays. Think about that for a while. — Some programmer dude, Jul 04 '13 at 09:22
actually i am beginner in programming. so dont mind if my question is too wild or lame...... — ranaarjun, Jul 04 '13 at 09:35

score 18 · Accepted Answer · edited Oct 21 '19 at 15:06

1) you can use 2D char array in this way

char names[5][100];

each line in the 2D array is an array of char with size = 100

for(i=0;i<5;i++)  
{
    printf(" Enter a name which you want to register\n");  
    scanf("%99s",names[i]);
}

2) You can use array of pointers in this way

char *names[5];

each element in the array is a pointer to a string (char array). you have to assign each pointer in the array to a memory space before you call scanf()

for(i=0;i<5;i++)  
{
    names[i]=malloc(100);  
    printf(" Enter a name which you want to register\n");  
    scanf("%99s",names[i]);
}

3) if you compile with gcc version >2.7 then your scanf() can allocate memory by using "%ms" instead of "%s"

char *names[5];
for(i=0;i<5;i++)  
{
    printf(" Enter a name which you want to register\n");  
    scanf("%ms",&names[i]);
}

I think there is a typo? add 's' after name? – Leonard Jun 27 '18 at 13:16 — Leonard, Jun 27 '18 at 13:16

score 0 · Answer 2 · edited May 01 '18 at 15:45

0

There is a simple example about reading and keeping string in the char array.

#include <stdio.h>

const int MACRO = 6;

int main() {
  printf("Hello Admin Please Enter the  Items:\n");

  char items[MACRO][20];

  for (int i = 0; i < MACRO; ++i) {
    scanf("%19s", items[i]);

  }

  for (int i = 0; i < MACRO; ++i) {
    printf("%s ", items[i]);
  }

  return 0;
}

edited May 01 '18 at 15:45

ADyson

57,178
14
51
63

answered May 01 '18 at 15:21

Berk Koylu

3
2

score 0 · Answer 3 · answered Jul 17 '20 at 12:10

In your program the mistake is that you have not putted '&'address of operator int the first for loop . names in your case is an array if you store %s string in names and not &names[0] or &names[1] or so on then as array itself acts as a pointer therefore the array "names" is pointing to the address of its first elements i.e. names[0] . so if you are writing scanf("%s",names); that is similar to scanf("%s",&names[0]); so as you are storing the names in one element only and that too for 5 iterations for only the last string you have entered will be stored and previous strings will be gone . so onlye last string is printed in your program .

Olivia. · Answer 4 · 2020-11-02T08:55:26.233

in your code, you only declare char data type to be one dimensional and thus it will always overwrite the previous input,that's why the result is the last input printed 5 times.

char names[10];

the above declaration means that you declare a char type variable only with 10 character size without an extra array,it means you only declare a single variable for 5 input.

to make a two dimensional char, you will need to declare it like this :

char names[5][10];

in the code above, it means that you declare a char type variable with 10 character size in an array of 5.

Raj Kumar · Answer 5 · 2018-06-03T15:39:29.057

Here is the code I wrote using pointer.

#include <stdio.h>
void main()
{
   char *string[100];
   int ln;

   printf("Enter numbar of lines: ");
   scanf("%d",&ln);
   printf("\n");
   for(int x=0;x<ln;x++)
   {    
     printf("Enter line no - %d ",(x+1));
     scanf("%ms",&string[x]);  // I am using gcc to compile file, that's why using %ms to allocate memory.              
   }
   printf("\n\n");
   for(int x=0;x<ln;x++)
   {            
     printf("Line No %d - %s \n",(x+1),string[x]);  
   }

}

Another code using two dimensional Array

    #include <stdio.h>

    void main()
    {

    int ln;

    printf("Enter numbar of lines: ");
    scanf("%d",&ln);
    printf("\n");

    char string[ln][10];

    for(int x=0;x<ln;x++){
        printf("Enter line no - %d ",(x+1));
        scanf("%s",&string[x][0]);
    }


    for(int x=0;x<ln;x++)
    {           
        printf("Line No %d - %s \n",(x+1),string[x]);   
    }



}

I recommend explaining what you did and why. Code only answers tend to result in little more than a marginal advancement in the asker's copy and paste skills. — user4581301, Jun 04 '18 at 04:42
I tried to explain two dimensional character array in second example also we can achieve the same result using pointer in 'C'. Please look at code. Actually I was also facing the same issue and I did it this way. — Raj Kumar, Jun 04 '18 at 09:08

Two Dimensional Array of Characters in C

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