sorting a struct array

I read a text file and stored the data in a struct array, then tried to sort it and to print the un-sorted and sorted arrays. It works up to reading the array text and storing in the array, but the sorting function does not run without giving any errors. what is wrong with it? I used the strcmp() function to compare student[s]:

#include <stdio.h>

struct person { //struct person with 4 fields
    char name[100];
    char address[100];
    char IDnumber[20];
    int  age;
};

int main (void) {
    FILE *file = fopen ( "personout.txt", "r");
    struct person student[10]; // declares an struct array to store data
    int k = 0;
    if (file != NULL) {
        char line[300];
        while ( k < 10 && fgets ( line, sizeof line, file ) != NULL ) {
            if ( 4 == sscanf ( line, " %99[^,], %99[^,], %19[^,], %d", 
                student[k].name, student[k].address, student[k].IDnumber, &student[k].age))
            {
                printf ( "%s\n Un-sorted array");
                printf ( "%s\n", student[k].name);
                printf ( "%s\n", student[k].address);
                printf ( "%s\n", student[k].IDnumber);
                printf ( "%d\n", student[k].age);
                k++;
            }
        }
        fclose ( file );
    }
    sortarray();

    // prints sorted array
    printf ( "%s\n Sorted array");
    for (int t=0;t<10;t++) {
        printf ( "%s\n", student[t].name);
        printf ( "%s\n", student[t].address);
        printf ( "%s\n", student[t].IDnumber);
        printf ( "%d\n", student[t].age);
        t++;
    }
}

void sortarray(){
    // number of records a  r=a first for loop
    // inner for loop s=r+1
    struct person temp,student[10];
    int a=10;
    for (int r=0;r<a-1;r++) {
        for (int s=r+1;r<a;s++) {
            if (strcmp(student[r].name, student[s].name) > 0) {
                temp = student[r];
                student[r] =student[s];
                student[s] = temp;
            }
        }
    }
}