In order to record balance sheet on android terminal
tiny calculator becomes to be needed
Please refer to source code about detail
#include <stdio.h>
#include <stdlib.h>
int main(){
        char buf[80];
        char operator;
        char str1[80];
        char str2[80];
        int datum1;
        int datum2;
        int i,j;

        while(1){
                i=j=0;
                scanf("%s",buf);
                while(buf[i] != '+' && buf[i] !='-')
                 str1[j++]= buf[i++];
                str1[j+1] = '\0';
                operator = buf[++i];
                j=0;
                while(buf[i]!='\0')
                        str2[j++]=buf[i++];
                str2[j+1]='\0';
                datum1 = atoi(str1);
                datum2 = atoi(str2);
                if(operator=='+')
                        printf("%d\n",datum1+datum2);
                else
                        printf("%d\n",datum1-datum2);
        }
}