Question

int readOptions(char *argv[]){
        FILE * infile;
        char line_buf[BUFSIZ];
        int i = 0, j = 0 ; 
        infile = fopen("options","r");
            if(!infile){

                     fprintf(stderr,"File Read failure\n");
                        exit(2);
            }

        while( i < 10 && fgets(line_buf,sizeof(line_buf),infile)!=0){

             printf("Line buf : %s",line_buf); 
             argv[i] =  line_buf;                                   

             i++;                               
}

}

int main(){

int j ; 

char *options[10]; 

for(j = 0 ; j< 10 ; j++){

        options[j] = malloc(len * sizeof (char));
    } 

 readOptions(options);
for(j=0; j<10 ; j++)
         printf("%s %d\n",options[j], j );

}

The problem is that I always see – the program print only the last line read in the file. Where is the mistake ? and am I missing any important pointer concept with this code ?

Answer 1

Every element of argv points to the same line_buf. Use strdup() to create new strings instead (which you will later have to free).