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fread() function in C language with Example

Here, we are going to learn about the fread() function of library header stdio.h in C language with its syntax, example.
Submitted by Souvik Saha, on January 11, 2019

fread() function in C

Prototype:

    size_t fread(void *buffer, size_t length, size_t count, FILE *filename);

Parameters:

    void *buffer, size_t length, size_t count, FILE *filename

Return type: size_t

Use of function:

The prototype of the function fread() is:

    size_t fread(void *buffer, size_t length, size_t count, FILE *filename);

In the file handling, through the fread() function, we read the count number of objects of size length from the input stream filename to the array named buffer. Its returns the number of objects being read from the file. If lesser no of objects are read or EOF is encountered before then it will give an error.

fread() example in C

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

int main()
{
    FILE* f;
    //initialize the arr1 with values
    int arr1[5] = { 1, 2, 3, 4, 5 };
    int arr2[5];
    int i = 0;

    //open the file for write operation
    if ((f = fopen("includehelp.txt", "w")) == NULL) {
        //if the file does not exist print the string
        printf("Cannot open the file...");
        exit(1);
    }
    //write the values on the file
    if ((fwrite(arr1, sizeof(int), 5, f)) != 5) {
        printf("File write error....\n");
    }
    //close the file
    fclose(f);

    //open the file for read operation
    if ((f = fopen("includehelp.txt", "r")) == NULL) {
        //if the file does not exist print the string
        printf("Cannot open the file...");
        exit(1);
    }
    //read the values from the file and store it into the array
    if ((fread(arr2, sizeof(int), 5, f)) != 5) {
        printf("File write error....\n");
    }
    fclose(f);

    printf("The array content is-\n");
    for (i = 0; i < 5; i++) {
        printf("%d\n", arr2[i]);
    }

    return 0;
}

Output

C stdio.h Library Functions Programs »

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