Question

Please help in C:

with the following code, i am getting a random 127 printed in front of my reverse display of the array. The file i am pulling (data.txt) is: 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9

when the reverse prints, it prints: 127 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1

not sure why...please help!!

code:

#include <stdio.h>
#include <stdlib.h>
#define MAX 100

void reverse(int data[MAX], int size, int i, int j, int flip);
void display(int data[MAX], int size, int i);

int main(){

//declare pointer
FILE *myFile;
//open the file in read
myFile = fopen("data.txt", "r");

//declare variables
int data[MAX];
int i = 0;
int size = 0;
int num = 0;
int j = 0;
int flip = 0;

//check if file is available and close with print statement if not
if (myFile == NULL){
printf("FILE NOT FOUND!!\n");
exit (0);
}

/*loop to read file data into array and
to increment size. Keeps looping until end of file*/
while(fscanf(myFile, "%d", &num)!=EOF){
data[size++] = num;
}

printf("Original Data:\n");
//call the function to print original data
display(data, size, i);

printf("\n");

printf("Flipped:\n");
reverse(data, size, i, j, flip);

printf("\n");

//close the file
fclose(myFile);

return 0;
}

//function to print original data
void display(int data[MAX], int size, int i){

printf("List =====> ");
for (i = 0; i < size; i++){
printf("%d ", data[i]);
}
printf("\n");
}

//function to flip original data and flip
void reverse(int data[MAX], int size, int i, int j, int flip){

for(i=0, j=size; i<j; i++, j--){
flip = data[i];
data[i] = data[j];
data[j] = flip;
}
printf("List =====> ");
for(i = 0; i < size; i++){
printf("%d ", data[i]);
}

}

Answer 1

#include <stdio.h>
#include <stdlib.h>

#define MAX 100

void reverse(int data[MAX], int size, int i, int j, int flip);

void display(int data[MAX], int size, int i);

int main() {

//declare pointer
    FILE *myFile;
//open the file in read
    myFile = fopen("data.txt", "r");

//declare variables
    int data[MAX];
    int i = 0;
    int size = 0;
    int num = 0;
    int j = 0;
    int flip = 0;

//check if file is available and close with print statement if not
    if (myFile == NULL) {
        printf("FILE NOT FOUND!!\n");
        exit(0);
    }

/*loop to read file data into array and
to increment size. Keeps looping until end of file*/
    while (fscanf(myFile, "%d", &num) != EOF) {
        data[size++] = num;
    }

    printf("Original Data:\n");
//call the function to print original data
    display(data, size, i);

    printf("\n");

    printf("Flipped:\n");
    reverse(data, size, i, j, flip);

    printf("\n");

//close the file
    fclose(myFile);
    return 0;
}

//function to print original data
void display(int data[MAX], int size, int i) {
    printf("List =====> ");
    for (i = 0; i < size; i++) {
        printf("%d ", data[i]);
    }
    printf("\n");
}

//function to flip original data and flip
void reverse(int data[MAX], int size, int i, int j, int flip) {
    for (i = 0, j = size-1; i < j; i++, j--) {  // use size-1 instead of size here
        flip = data[i];
        data[i] = data[j];
        data[j] = flip;
    }
    printf("List =====> ");
    for (i = 0; i < size; i++) {
        printf("%d ", data[i]);
    }
}