5-8

#include<stdio.h>
float cash;
int main(void)
{
    int choice;
    float value;
    void income(float number),expend(float number);

    cash=0;
    printf("Enter operate choice(0--end,1--income,2--expend):");
    scanf("%d",&choice);
    while(choice!=0){
        if(choice==1||choice==2){
            printf("Enter cash value:");
            scanf("%f",&value);
            if(choice==1)
                income(value);
            else
                expend(value);
            printf("current cash:%.2f\n",cash);
        }
        printf("Enter operate choice(0--end,1--income,2--expend):");
        scanf("%d",&choice);
    }

    return 0;
}
void income(float number)
{
    cash=cash+number;
}

void expend(float number)
{
    cash=cash-number;
}