Sorting array structures

How do I sort arrays structures? I just need a quick explanation or small ex. to lead me in the direction.

Code:

*/ This program requires three command arguments: The text file name, the number of entries to be scanned from the input file, and the input file name. The program will scan the input file's entries into a structured array and sort the arrays. It will also print the unsorted and sorted arrays. Lasltly, it will allow the user to run queries for certain entries using the SSN. *****************************************************************************/ /* Preprocessing Directives */ #include <stdio.h> #include <stdbool.h> #include <stdlib.h> #define LEN 30 #define NUM 10 typedef struct { int month; int day; int year; } BDATE; typedef struct { char firstName[LEN]; char lastName[LEN] ; int grade; char SSN [10]; BDATE bDate; } STUDENT; void displayName (); bool openFile (char *argv[], FILE* *pfpIn); bool readFile (char *argv[], FILE* afpIn, STUDENT stud[]); void displayFile (char *argv[], STUDENT stud[]); void sortName (char *argv[], STUDENT stud[]); void displaySortName (char *argv[], STUDENT stud[]); void sortSSN (); void displaySortSSN (); void binSearch (); // Function main calls other functions and returns control back to OS. int main (int argc, char *argv[]) { int quant = atoi (argv[1]); STUDENT stud[NUM]; FILE* afpIn; displayName (); if (argc == 3 && quant > 1 && quant < 10) { printf("\nNumber of command arguments: %d", argc); printf("\nNumber of strings to scan from file: %s", argv[1]); printf("\nName of input file: %s", argv[2]); if ( openFile (argv, &afpIn) && readFile(argv, afpIn, stud) ) { displayFile(argv, stud); sortName(argv, stud); displaySortName(argv, stud); } } else ("\nPlease try again later\n"); return 0; } // Function displayName displays the Programmer's name. void displayName() { printf("\nThomas Ciocco\n"); } // Function openFile opens the input file bool openFile (char *argv[], FILE* *pfpIn) { bool openFileSuccess = false; if ((*pfpIn = fopen (argv[2], "r")) != NULL) { openFileSuccess = true; printf ("\nFile open success\n\n"); } else printf("\nFile did not open successfully\n"); return openFileSuccess; } // Function readFile scans the input file data into a structured array bool readFile (char *argv[], FILE* afpIn, STUDENT stud[]) { bool readFileSuccess = true; int counter; int quant = atoi (argv[1]); char* tempMonth[quant][LEN]; char* tempDay[quant][LEN]; char* tempYear[quant][LEN]; for (counter = 0; counter < quant ; counter++) { fscanf(afpIn, "%s %s %d %s %s %s %s", stud[counter].firstName, stud[counter].lastName, &stud[counter].grade, stud[counter].SSN, tempMonth[counter], tempDay[counter], tempYear[counter]); } // Converts file month strings to ints and fills bDate.month for (counter = 0; counter < quant; counter++) { if(!strcmp(tempMonth[counter],"January")) { stud[counter].bDate.month = 1; } if(!strcmp(tempMonth[counter],"February")) { stud[counter].bDate.month = 2; } if(!strcmp(tempMonth[counter],"March")) { stud[counter].bDate.month = 3; } if(!strcmp(tempMonth[counter],"April")) { stud[counter].bDate.month = 4; } if(!strcmp(tempMonth[counter],"May")) { stud[counter].bDate.month = 5; } if(!strcmp(tempMonth[counter],"June")) { stud[counter].bDate.month = 6; } if(!strcmp(tempMonth[counter],"July")) { stud[counter].bDate.month = 7; } if(!strcmp(tempMonth[counter],"August")) { stud[counter].bDate.month = 8; } if(!strcmp(tempMonth[counter],"September")) { stud[counter].bDate.month = 9; } if(!strcmp(tempMonth[counter],"October")) { stud[counter].bDate.month = 10; } if(!strcmp(tempMonth[counter],"November")) { stud[counter].bDate.month = 11; } if(!strcmp(tempMonth[counter],"December")) { stud[counter].bDate.month = 12; } } // Converts string days and months to ints and fills bDate.day and year for (counter = 0; counter < quant; counter++) { stud[counter].bDate.day = atoi(tempDay[counter]); stud[counter].bDate.year = atoi(tempYear[counter]); } return readFileSuccess; } // Function displayFile prints the file data void displayFile (char *argv[], STUDENT stud[]) { int counter; int quant; quant = atoi (argv[1]); printf(" Name"); printf(" Level"); printf(" SSN"); printf(" BirthDate\n"); printf(" ----"); printf(" -----"); printf(" ---"); printf(" ---------\n"); for (counter = 0; counter < quant; counter++) { printf("%10s %10s %7d %15s %5d/%d/%d \n", stud[counter].firstName, stud[counter].lastName, stud[counter].grade, stud[counter].SSN, stud[counter].bDate.month, stud[counter].bDate.day, stud[counter].bDate.year); } } // Function sortName sorts the array by Name data void sortName (char *argv[], STUDENT stud[]) { int quant = atoi (argv[1]); int last; int current; int walk; int smallest; int tempData; STUDENT temp[quant]; } // Function displaySortName prints the array sorted by name void displaySortName(char *argv[], STUDENT stud[]) { int counter; int quant; int last; STUDENT temp; STUDENT* pCurrent; STUDENT* pWalker; STUDENT* pSmallest; quant = atoi (argv[1]); last = quant + 1; for (counter= 0; counter < last; counter++) { ; } } // Function sortSSN sorts the array by the SSN void sortSSN ( ) { } // Function displaySortSSN prints the array sorted by SSN void displaySortSSN ( ) { } // Function binSearch allows user to search database for entry via SSN void binSearch ( ) { }