Small error in my program C Language -

so program not outputting proper value numdeposit or numcheck, outputs value of 0 both of these. think prime area of interest main function , bottom function can't see did wrong.

#include <stdio.h> #include <stdlib.h>  file *csis;  file *fp;  void outputheaders();  void initialbalance(double amount, double *balance, double *service, double *openbalance);  void deposit(double amount, double *balance, double *service, int *numdeposit, double *amtdeposit);  void check(double amount, double *balance, double *service, int *numcheck, double *amtcheck);  void outputsummary(int numdeposit, double amtdeposit, int numcheck, double amtcheck, double openbalance, double service, double closebalance);   int main(void) {      char code;     double amount, service, balance;     double amtcheck, amtdeposit, openbalance, closebalance;     int numcheck, numdeposit;      if (!(fp = fopen("account.txt", "r"))) {         printf("account.txt not opened input.");         fprintf(csis, "account.txt not opened input.");         exit(1);     }     if (!(csis = fopen("csis.txt", "w"))) {         printf("csis.txt not opened output.");         fprintf(csis, "csis.txt not opened output.");             exit(1);     }      amount = 0.0;     service = 0.0;     balance = 0.0;     amtcheck = 0.0;     amtdeposit = 0.0;     openbalance = 0.0;     closebalance = 0.0;     numcheck = 0;     numdeposit = 0;      outputheaders();      while (!feof(fp)) {         fscanf(fp, "%c %lf\n", &code, &amount);         if (code == 'i'){             initialbalance(amount, &balance, &service, &openbalance);         }         else if (code == 'd') {             deposit(amount, &balance, &service, &numdeposit, &amtdeposit);         }         else {             check(amount, &balance, &service, &numcheck, &amtcheck);         }     }      closebalance = balance - service;     outputsummary(numdeposit, amtdeposit, numcheck, amtcheck, openbalance, service, closebalance);     getch();     fclose(csis);     fclose(fp);     return 0; }  void outputheaders(){      printf("transaction\tdeposit\tcheck\tbalance\n");      printf("-----------\t-------\t-----\t-------\n");  }  void initialbalance(double amount, double *balance, double *service, double *openbalance){      *service += 3;     *balance += amount;     *openbalance = amount;     printf("initial balance\t\t\t%.2f\n", amount); }  void deposit(double amount, double *balance, double *service, int *numdeposit, double *amtdeposit){      *balance += amount;     *service += .03;     *numdeposit++;     *amtdeposit += amount;     printf("deposit\t\t%.2f\t\t%.2f\n", amount, *balance); }  void check(double amount, double *balance, double *service, int *numcheck, double *amtcheck){      *balance -= amount;     *service += .06;     *numcheck++;     *amtcheck += amount;     if (*balance < 0){         *service += 5;     }     printf("check\t\t\t%.2f\t%.2f\n", amount, *balance); }  void outputsummary(int numdeposit, double amtdeposit, int numcheck, double amtcheck, double openbalance, double service, double closebalance){      printf("\nsummary\n---------------------------------------\n");     printf("opening balance: %.2f\n", openbalance);     printf("number of deposits: %d \tamount deposited: %.2f\n", numdeposit, amtdeposit);     printf("number of checks: %d \tamount checked: %.2f\n", numcheck, amtcheck);     printf("service charges: %.2f\n", service);     printf("closing balance: %.2f\n", closebalance); } 

it's operator precedence issue.

*numdeposit++; 

the postfix ++ has higher precedence *. it's evaluating to

*(numdeposit++); 

which nothing (it increments pointer references value @ memory location). can do

(*numdeposit)++; 

or

*numdeposit += 1; 

see http://en.cppreference.com/w/cpp/language/operator_precedence.