问在C: 2打印输出时，我只需要一个输出。

EN

#include <stdio.h>

int main(void)
{
    float amount, old, new;
    char letter;

    printf("Please enter your current balance: ");
    scanf("%f", &old);

    printf("Enter the kind  of transaction you would like: W - withdrawl, D - deposit, F - finished. \n");
    scanf("%c", &letter);

    while (letter != 'F'){

        if (letter == 'D'){
            printf("Amount: ");
            scanf("%f", &amount);
            new = old + amount;
            old = new;
        }

        if (letter == 'W'){
            printf("Amount: ");
            scanf("%f", &amount);
            new = old - amount;
            old = new;
        }

    printf("Enter transaction: ");
    scanf("%c", &letter);
    }

    if (letter == 'F')
        printf("Your ending balance is %f.\n", old);

    return 0;