2d array giving wrong output











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1
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I was writing a code to print all the strings stored in 2d array after the user has finished typing the strings along with mentioning the maxlength of each string and total number strings (it will finally print the string along with the line number). The problem is that the code actually stores all the strings in the 2d array with one whole line of spacing i.e, one full empty row. The code, expected output and the output it is giving is below.



Code:



#include <stdio.h>



int main() {

    char s[20][30];

    int i, number_of_strings, length_of_string, j = 0;

    scanf("%d %d", &number_of_strings, &length_of_string);



    for (i = 0; i<number_of_strings; i++) {

        while ((s[i][j++] = getchar()) != 'n' && j<length_of_string)

            s[i][j] = '';

        j = 0;

    }



    for (i = 0; i<number_of_strings; i++) {

        printf("i= %d   %sn", i, s[i]);

    }



    return 0;

}


Sample Input:



2 3

raj

jar


Expected Output:



i= 0   raj

i= 1   jar


Output giving:



i= 0   



i= 1   raj

i= 2    



i= 3   jar


Please rectify where am I doing mistake.






c multidimensional-array output







share|improve this question




















  • 1




    Do you realize you have a newline stuck in your input buffer after you second int read ? what do you suppose that does to your first loop iteration ?
    – WhozCraig
    Nov 12 at 8:02






  • 1




    You need to eat the n before it consumes in your next iteration.
    – jack jay
    Nov 12 at 8:04






  • 1




    scanf("%d %d", &number_of_strings, &length_of_string); leaves the n of 2 3n in the buffer and the first getchar() reads it.
    – mch
    Nov 12 at 8:04






  • 1




    while ((s[i][j++] = getchar()) != 'n' && j<length_of_string) s[i][j] = ''; ==> size test first as (j + 1) <length_of_string
    – chux
    Nov 12 at 8:04








  • 1




    @KaustavBhattacharjee n is in your buffer. This is the problem.
    – jack jay
    Nov 12 at 8:06

















up vote
1
down vote

favorite












I was writing a code to print all the strings stored in 2d array after the user has finished typing the strings along with mentioning the maxlength of each string and total number strings (it will finally print the string along with the line number). The problem is that the code actually stores all the strings in the 2d array with one whole line of spacing i.e, one full empty row. The code, expected output and the output it is giving is below.



Code:



#include <stdio.h>



int main() {

    char s[20][30];

    int i, number_of_strings, length_of_string, j = 0;

    scanf("%d %d", &number_of_strings, &length_of_string);



    for (i = 0; i<number_of_strings; i++) {

        while ((s[i][j++] = getchar()) != 'n' && j<length_of_string)

            s[i][j] = '';

        j = 0;

    }



    for (i = 0; i<number_of_strings; i++) {

        printf("i= %d   %sn", i, s[i]);

    }



    return 0;

}


Sample Input:



2 3

raj

jar


Expected Output:



i= 0   raj

i= 1   jar


Output giving:



i= 0   



i= 1   raj

i= 2    



i= 3   jar


Please rectify where am I doing mistake.






c multidimensional-array output







share|improve this question




















  • 1




    Do you realize you have a newline stuck in your input buffer after you second int read ? what do you suppose that does to your first loop iteration ?
    – WhozCraig
    Nov 12 at 8:02






  • 1




    You need to eat the n before it consumes in your next iteration.
    – jack jay
    Nov 12 at 8:04






  • 1




    scanf("%d %d", &number_of_strings, &length_of_string); leaves the n of 2 3n in the buffer and the first getchar() reads it.
    – mch
    Nov 12 at 8:04






  • 1




    while ((s[i][j++] = getchar()) != 'n' && j<length_of_string) s[i][j] = ''; ==> size test first as (j + 1) <length_of_string
    – chux
    Nov 12 at 8:04








  • 1




    @KaustavBhattacharjee n is in your buffer. This is the problem.
    – jack jay
    Nov 12 at 8:06















up vote
1
down vote

favorite









up vote
1
down vote

favorite











I was writing a code to print all the strings stored in 2d array after the user has finished typing the strings along with mentioning the maxlength of each string and total number strings (it will finally print the string along with the line number). The problem is that the code actually stores all the strings in the 2d array with one whole line of spacing i.e, one full empty row. The code, expected output and the output it is giving is below.



Code:



#include <stdio.h>



int main() {

    char s[20][30];

    int i, number_of_strings, length_of_string, j = 0;

    scanf("%d %d", &number_of_strings, &length_of_string);



    for (i = 0; i<number_of_strings; i++) {

        while ((s[i][j++] = getchar()) != 'n' && j<length_of_string)

            s[i][j] = '';

        j = 0;

    }



    for (i = 0; i<number_of_strings; i++) {

        printf("i= %d   %sn", i, s[i]);

    }



    return 0;

}


Sample Input:



2 3

raj

jar


Expected Output:



i= 0   raj

i= 1   jar


Output giving:



i= 0   



i= 1   raj

i= 2    



i= 3   jar


Please rectify where am I doing mistake.






c multidimensional-array output







share|improve this question















I was writing a code to print all the strings stored in 2d array after the user has finished typing the strings along with mentioning the maxlength of each string and total number strings (it will finally print the string along with the line number). The problem is that the code actually stores all the strings in the 2d array with one whole line of spacing i.e, one full empty row. The code, expected output and the output it is giving is below.



Code:



#include <stdio.h>



int main() {

    char s[20][30];

    int i, number_of_strings, length_of_string, j = 0;

    scanf("%d %d", &number_of_strings, &length_of_string);



    for (i = 0; i<number_of_strings; i++) {

        while ((s[i][j++] = getchar()) != 'n' && j<length_of_string)

            s[i][j] = '';

        j = 0;

    }



    for (i = 0; i<number_of_strings; i++) {

        printf("i= %d   %sn", i, s[i]);

    }



    return 0;

}


Sample Input:



2 3

raj

jar


Expected Output:



i= 0   raj

i= 1   jar


Output giving:



i= 0   



i= 1   raj

i= 2    



i= 3   jar


Please rectify where am I doing mistake.






c multidimensional-array output




c multidimensional-array output






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 12 at 8:03

























asked Nov 12 at 7:57









Kaustav Bhattacharjee

114




114








  • 1




    Do you realize you have a newline stuck in your input buffer after you second int read ? what do you suppose that does to your first loop iteration ?
    – WhozCraig
    Nov 12 at 8:02






  • 1




    You need to eat the n before it consumes in your next iteration.
    – jack jay
    Nov 12 at 8:04






  • 1




    scanf("%d %d", &number_of_strings, &length_of_string); leaves the n of 2 3n in the buffer and the first getchar() reads it.
    – mch
    Nov 12 at 8:04






  • 1




    while ((s[i][j++] = getchar()) != 'n' && j<length_of_string) s[i][j] = ''; ==> size test first as (j + 1) <length_of_string
    – chux
    Nov 12 at 8:04








  • 1




    @KaustavBhattacharjee n is in your buffer. This is the problem.
    – jack jay
    Nov 12 at 8:06
















  • 1




    Do you realize you have a newline stuck in your input buffer after you second int read ? what do you suppose that does to your first loop iteration ?
    – WhozCraig
    Nov 12 at 8:02






  • 1




    You need to eat the n before it consumes in your next iteration.
    – jack jay
    Nov 12 at 8:04






  • 1




    scanf("%d %d", &number_of_strings, &length_of_string); leaves the n of 2 3n in the buffer and the first getchar() reads it.
    – mch
    Nov 12 at 8:04






  • 1




    while ((s[i][j++] = getchar()) != 'n' && j<length_of_string) s[i][j] = ''; ==> size test first as (j + 1) <length_of_string
    – chux
    Nov 12 at 8:04








  • 1




    @KaustavBhattacharjee n is in your buffer. This is the problem.
    – jack jay
    Nov 12 at 8:06










1




1




Do you realize you have a newline stuck in your input buffer after you second int read ? what do you suppose that does to your first loop iteration ?
– WhozCraig
Nov 12 at 8:02




Do you realize you have a newline stuck in your input buffer after you second int read ? what do you suppose that does to your first loop iteration ?
– WhozCraig
Nov 12 at 8:02




1




1




You need to eat the n before it consumes in your next iteration.
– jack jay
Nov 12 at 8:04




You need to eat the n before it consumes in your next iteration.
– jack jay
Nov 12 at 8:04




1




1




scanf("%d %d", &number_of_strings, &length_of_string); leaves the n of 2 3n in the buffer and the first getchar() reads it.
– mch
Nov 12 at 8:04




scanf("%d %d", &number_of_strings, &length_of_string); leaves the n of 2 3n in the buffer and the first getchar() reads it.
– mch
Nov 12 at 8:04




1




1




while ((s[i][j++] = getchar()) != 'n' && j<length_of_string) s[i][j] = ''; ==> size test first as (j + 1) <length_of_string
– chux
Nov 12 at 8:04






while ((s[i][j++] = getchar()) != 'n' && j<length_of_string) s[i][j] = ''; ==> size test first as (j + 1) <length_of_string
– chux
Nov 12 at 8:04






1




1




@KaustavBhattacharjee n is in your buffer. This is the problem.
– jack jay
Nov 12 at 8:06






@KaustavBhattacharjee n is in your buffer. This is the problem.
– jack jay
Nov 12 at 8:06














1 Answer
1






active

oldest

votes

















up vote
1
down vote



accepted










You've hit one of the many issues with scanf. In this case scanf("%d %d", ...) is leaving a newline on the buffer. You can get it to slurp in trailing whitespace with a space on the end.



scanf("%d %d ", &number_of_strings , &length_of_string);


Then how you're reading a line is complicated. You can simplify it like so:



 int c, j;

 for(j = 0; (c = getchar()) != 'n'; j++ ) {

     s[i][j] = (char)c;

 }

 s[i][j] = '';


Or even simpler...



for(int i=0 ; i<number_of_strings ; i++) {

    scanf("%29s", s[i]);

}


And there's no need for length_of_string. In fact, it's a liability since you've only allocated 30 bytes max. Similarly, number_of_strings can be higher than the allocated 20. It's better to read until input or memory is exhausted.



#include <stdio.h>



const int MAX_STRINGS = 20;

const int MAX_LENGTH = 30;

int main(){ 

    char s[MAX_STRINGS][MAX_LENGTH];

    int num_strings;

    for(num_strings = 0; num_strings < MAX_STRINGS ; num_strings++) {

        if( scanf("%29s", s[num_strings]) < 1 ) {

            break;

        }

    }



    for( int i = 0 ; i < num_strings; i++){                                                                               

        printf("i= %d   %sn",i,s[i]);

    }



    return 0;      

}





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    1 Answer
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    active

    oldest

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    up vote
    1
    down vote



    accepted










    You've hit one of the many issues with scanf. In this case scanf("%d %d", ...) is leaving a newline on the buffer. You can get it to slurp in trailing whitespace with a space on the end.



    scanf("%d %d ", &number_of_strings , &length_of_string);


    Then how you're reading a line is complicated. You can simplify it like so:



     int c, j;
    
 for(j = 0; (c = getchar()) != 'n'; j++ ) {
    
     s[i][j] = (char)c;
    
 }
    
 s[i][j] = '';


    Or even simpler...



    for(int i=0 ; i<number_of_strings ; i++) {
    
    scanf("%29s", s[i]);
    
}


    And there's no need for length_of_string. In fact, it's a liability since you've only allocated 30 bytes max. Similarly, number_of_strings can be higher than the allocated 20. It's better to read until input or memory is exhausted.



    #include <stdio.h>
    

    
const int MAX_STRINGS = 20;
    
const int MAX_LENGTH = 30;
    
int main(){ 
    
    char s[MAX_STRINGS][MAX_LENGTH];
    
    int num_strings;
    
    for(num_strings = 0; num_strings < MAX_STRINGS ; num_strings++) {
    
        if( scanf("%29s", s[num_strings]) < 1 ) {
    
            break;
    
        }
    
    }
    

    
    for( int i = 0 ; i < num_strings; i++){                                                                               
    
        printf("i= %d   %sn",i,s[i]);
    
    }
    

    
    return 0;      
    
}





    share|improve this answer



























      up vote
      1
      down vote



      accepted










      You've hit one of the many issues with scanf. In this case scanf("%d %d", ...) is leaving a newline on the buffer. You can get it to slurp in trailing whitespace with a space on the end.



      scanf("%d %d ", &number_of_strings , &length_of_string);


      Then how you're reading a line is complicated. You can simplify it like so:



       int c, j;
      
 for(j = 0; (c = getchar()) != 'n'; j++ ) {
      
     s[i][j] = (char)c;
      
 }
      
 s[i][j] = '';


      Or even simpler...



      for(int i=0 ; i<number_of_strings ; i++) {
      
    scanf("%29s", s[i]);
      
}


      And there's no need for length_of_string. In fact, it's a liability since you've only allocated 30 bytes max. Similarly, number_of_strings can be higher than the allocated 20. It's better to read until input or memory is exhausted.



      #include <stdio.h>
      

      
const int MAX_STRINGS = 20;
      
const int MAX_LENGTH = 30;
      
int main(){ 
      
    char s[MAX_STRINGS][MAX_LENGTH];
      
    int num_strings;
      
    for(num_strings = 0; num_strings < MAX_STRINGS ; num_strings++) {
      
        if( scanf("%29s", s[num_strings]) < 1 ) {
      
            break;
      
        }
      
    }
      

      
    for( int i = 0 ; i < num_strings; i++){                                                                               
      
        printf("i= %d   %sn",i,s[i]);
      
    }
      

      
    return 0;      
      
}





      share|improve this answer

























        up vote
        1
        down vote



        accepted







        up vote
        1
        down vote



        accepted






        You've hit one of the many issues with scanf. In this case scanf("%d %d", ...) is leaving a newline on the buffer. You can get it to slurp in trailing whitespace with a space on the end.



        scanf("%d %d ", &number_of_strings , &length_of_string);


        Then how you're reading a line is complicated. You can simplify it like so:



         int c, j;
        
 for(j = 0; (c = getchar()) != 'n'; j++ ) {
        
     s[i][j] = (char)c;
        
 }
        
 s[i][j] = '';


        Or even simpler...



        for(int i=0 ; i<number_of_strings ; i++) {
        
    scanf("%29s", s[i]);
        
}


        And there's no need for length_of_string. In fact, it's a liability since you've only allocated 30 bytes max. Similarly, number_of_strings can be higher than the allocated 20. It's better to read until input or memory is exhausted.



        #include <stdio.h>
        

        
const int MAX_STRINGS = 20;
        
const int MAX_LENGTH = 30;
        
int main(){ 
        
    char s[MAX_STRINGS][MAX_LENGTH];
        
    int num_strings;
        
    for(num_strings = 0; num_strings < MAX_STRINGS ; num_strings++) {
        
        if( scanf("%29s", s[num_strings]) < 1 ) {
        
            break;
        
        }
        
    }
        

        
    for( int i = 0 ; i < num_strings; i++){                                                                               
        
        printf("i= %d   %sn",i,s[i]);
        
    }
        

        
    return 0;      
        
}





        share|improve this answer














        You've hit one of the many issues with scanf. In this case scanf("%d %d", ...) is leaving a newline on the buffer. You can get it to slurp in trailing whitespace with a space on the end.



        scanf("%d %d ", &number_of_strings , &length_of_string);


        Then how you're reading a line is complicated. You can simplify it like so:



         int c, j;
        
 for(j = 0; (c = getchar()) != 'n'; j++ ) {
        
     s[i][j] = (char)c;
        
 }
        
 s[i][j] = '';


        Or even simpler...



        for(int i=0 ; i<number_of_strings ; i++) {
        
    scanf("%29s", s[i]);
        
}


        And there's no need for length_of_string. In fact, it's a liability since you've only allocated 30 bytes max. Similarly, number_of_strings can be higher than the allocated 20. It's better to read until input or memory is exhausted.



        #include <stdio.h>
        

        
const int MAX_STRINGS = 20;
        
const int MAX_LENGTH = 30;
        
int main(){ 
        
    char s[MAX_STRINGS][MAX_LENGTH];
        
    int num_strings;
        
    for(num_strings = 0; num_strings < MAX_STRINGS ; num_strings++) {
        
        if( scanf("%29s", s[num_strings]) < 1 ) {
        
            break;
        
        }
        
    }
        

        
    for( int i = 0 ; i < num_strings; i++){                                                                               
        
        printf("i= %d   %sn",i,s[i]);
        
    }
        

        
    return 0;      
        
}






        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited Nov 12 at 8:17

























        answered Nov 12 at 8:09









        Schwern

        87.9k16101229




        87.9k16101229






























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