Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// number of salesman
#define SIZE 100
// salesman_type structure definition
typedef struct{
int ID; // salesman id
char id_txt[6]; // salesman id for txt file
char name[50]; // salesman name
double hor_total; // total sales amount of a salesman
}salesman_type; // end structure salesman_type
salesman_type salesman[SIZE];// synonym for salesman_type
// function prototype
int nextId(int currentId, int isReset);
int sale_menu();
void modifySales();
// function to generate id
// currentId and isReset are parameters
int nextId(int currentId, int isReset)
{
// initializes elements to 0 for the first time function is called
static int lastId = 0;
// if isReset is 0, assign currentId to lastId;
if (isReset == 0)
{
lastId = currentId;
}
//if isReset is not 0, return and add 1 to lastId
if (isReset != 0)
return ++lastId;
} // end function nextId
// sales processing system menu function
int sale_menu()
{
int menu;
system("cls");
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);
return menu;
printf("\n");
}// end function sale_menu
void modifySales()
{
FILE *salesPtr; // sales.txt file pointer
FILE *salesmanPtr; // salesman.txt file pointer
FILE *tempSalesPtr; // temp.txt file pointer
int a, b, modify; // counter
double sale[SIZE][4]; // quartely sales amount
// fopen opens the file; exits program if file cannot be opened
if ( (salesPtr = fopen("sales.txt","r")) == NULL )
{
printf("Cannot open sales.txt\n"); // display error message
system("pause"); // pause program before it exits
exit(-1); // end program
} // end if
else
{
// fopen opens the file; exits program if file cannot be opened
if ( (salesmanPtr = fopen("salesman.txt","r")) == NULL)
{
printf("Cannot open salesman.txt"); // display error message
system("pause"); // pause program before it exits
exit(-1); // end program
} // end if
else
{
tempSalesPtr = fopen("temp.txt","w");
// prompt and read salesman id
printf("\nSalesman ID (NO.): ");
scanf("%d",&modify);
for(a=0; a<SIZE; a++)
{
// read salesman id from file if there are still have salesman id
if ((fscanf(salesPtr,"%[^|]|", salesman[a].id_txt) ) == 1 )
{
fprintf(tempSalesPtr,"%s|",salesman[a].id_txt);
// read salesman name
//fscanf(salesmanPtr,"%*[^\n]\n%*s\t\t%[^\n]\n%*[^\n]\n%*[^\n]\n%*[^\n]\n\n",salesman[a].name);
for (b=0; b<4; b++)
{ // read quarterly sales amount
if(b<3)
{
if (a != modify - 1)
{
fscanf(salesPtr,"%lf|", &sale[a][b]);
}
else
{
printf("Quarter %d: ",b+1);
scanf("%lf",&sale[a][b]);
}
fprintf(tempSalesPtr,"%.2f|",sale[a][b]);
}// end if
else
{
if (a != modify - 1)
{
fscanf(salesPtr,"%lf\n", &sale[a][b]);
}
else
{
printf("Quarter %d: ",b+1);
scanf("%lf",&sale[a][b]);
}
fprintf(tempSalesPtr,"%.2f\n",sale[a][b]);
}// end else
} // end for
if (a == modify - 1)
{
fscanf(salesPtr,"%*[^\n]\n");
}
} // end if
} // end for
} // end else
fclose(salesPtr); // fclose close the file
} // end else
fclose(salesmanPtr); // fclose close the file
fclose(tempSalesPtr);
system("pause");
}
// function main begins program execution
int main()
{
// nextid.txt file pointer
FILE *readIdPtr;
// variable declaration
int a, b, c = 0, last; // counter
int getMenu = 10, getReport = 10; // menu selector
double ver_total = 0, max = 0;
int id = 0, lastId, resetId = 0;
// fopen opens the file; exits program if file cannot be opened
if ( (readIdPtr = fopen("nextid.txt","r") ) == NULL)
{
printf("Cannot open nextid.txt file\n");
system("pause");
exit(-1);
} // end if
else
{
// read lastId from file
fscanf(readIdPtr,"%d",&lastId);
// Generate new id from previous salesman ID if the salesman is one or more
// lastId and restId are arguments
nextId(lastId, resetId);
} // end else
// fclose close the file
fclose(readIdPtr);
printf("\n");
while (getMenu != 0)
{
// call and assign sale_menu function to getMenu
// Execute command based on user input
switch(getMenu = sale_menu())
{
case 1:
break;
// call report_menu function
case 2:
break;
case 3:
modifySales();
break;
} // end switch
}// end while
system("pause"); // pause the program before it exits
return 0;
} // end main
I already done it. Thanks to 
Originally Posted by ulti-killer
