Code:
typedef struct{
		int ID;
		char name[50];
		double hor_total;
	}group;
	group salesman[SIZE];


void sale_menu();
void AddSalesMan();
int nextid();

void sale_menu(int menu)
{
	printf("Sales Processing System\n");
	printf("-----------------------\n\n");
	printf("1. Add Salesman Records\n");
	printf("2. Reports Generation\n");
	printf("3. Modify Salesman Records\n");
	printf("4. Delete Salesman Records\n\n");
	printf("0. Exit\n");
	printf("Your choice: ");
	scanf("%d", &menu);
}

void AddSalesMan()
{
	FILE *inSales;
	int a, b;


	if ( (inSales = fopen("sales.txt","a")) == NULL)
		printf("Cannot open sales.txt file.");
	else
	{
		fprintf(inSales,"\n");
		for(a=0; a<SIZE; a++)
		{
			fprintf(inSales,"S%04d|",salesman[a].ID);


			for (b=0; b<4; b++)
			{
				printf("Quarter %d: ",b+1);
				scanf(" %lf", &sale[a][b]);
				fprintf(inSales,"%lf|",sale[a][b]);
			}	
		}	
	}
	fclose(inSales);
}


int nextid(int currentId, int isReset)
{
	static int lastId = 0;
	if (isReset)
	{
		lastId = currentId;
	}
	return ++lastId;
	
}




// function main begins program executionvoid main()
{
	// file pointer for nextid.txt
	FILE *readId;
	// variable declaration
	int a, b, c = 0, last, getMenu = 0; 
	double ver_total = 0, max = 0; 
	int id = 0, lastId, resetId = 0;


	
	// if readId(open nextid.txt) is NULL, display message
	if ( (readId = fopen("nextid.txt","r")) == NULL)
		printf("Cannot open nextid.txt file");
	else
	{
		// read previous id numbering from nextid.txt
		fscanf(readId,"%d",&lastId);
		// Pass lastId and resetId arguments to nextid function call
		nextid(lastId, resetId);
	}
	// close readId file pointer
	fclose(readId);


	// Initialize salesman id and salesman horizontal total value
	for(a=0; a<SIZE; a++) 
	{
		salesman[a].ID = nextid(lastId, resetId);
		salesman[a].hor_total = 0;
	}


	// call sale_menu function
	sale_menu(getMenu);
	
	// if getMenu = 1, call AddSalesMan function
	if (getMenu == 1)
		AddSalesMan();
}
Why AddSalesMan() function cannot execute?