c - How to read a multi line using fscanf -

i want read data.txt file looks , store in array called buffer[i][j]

1 1 1 1

2 2 2 2

3 3 3 3

4 4 4 4

i writing code looks like

#include"stdio.h" #include"stdlib.h"  int main() {    file *fp1;   int i,j;    int buffer[4][4]={0};    fp1 = fopen("exact_enumerated_config_442_cub_mc","r");    for(i=0;i<4;i++) {     for(j=0;j<4;j++) {       fscanf(fp1,"%d", &buffer[i][j]);     }     // fscanf(fp1,"\n");   }   fclose(fp1);    for(i=0;i<4;i++) {     for(j=0;j<4;j++) {       printf("%d ",buffer[i][j]);     }     printf("\n");   } } 

but output...

1 1 2 1

5 1 6 1

17 1 18 1

21 1 22 1

why????

• always check result of fopen() ensure file has been opened.
• always check result of fscanf() ensure successful , prevent subsequent code processing variables may not have been assigned value (it returns number of assignments made).
• add leading space character format specifier skip whitespace, including newline characters: " %d".

the code treat single line sixteen ints same 4 lines 4 ints. if important format of file 4 ints per line read single line using fgets() , use sscanf() extract ints %n format specifier ensure full buffer processed:

int ints[4][4] = { { 0 } }; char buffer[1024]; (int = 0; < 4 && fgets(buffer, 1024, fp); i++) {     int pos;     if (sscanf(buffer,                "%d %d %d %d%n",                &ints[i][0],                &ints[i][1],                &ints[i][2],                &ints[i][3],                &pos) != 4 || pos != strlen(buffer) - 1)     {         fprintf(stderr, "invalid format: <%s>\n", buffer);         exit(1);     } }