Implementing a calculator (+, -, ×, ÷) in C language.
Higher category : 【C Language】 C Language Index
a. Github
#include <stdio.h>
#include <stdlib.h>
#define Max 100
/* This source is for calculation at practical input situation */
// Devision on this calculator prints quota.
// If you want real Devision, you should change the format (Now the format is 'int')
int Calculator_I(char *Array, int Array_Size); // seperator; separate by each monomials; + and -
int Calculator_II(char *Array, int Array_Size); // calculate a monomial; * and /
int Calculator_I(char *Array, int Array_Size){ // 'a*(b+c) + d' >> 'a*(b+c)' and 'd'
if(Array_Size == 0) return 0; // for the case that initial number < 0
int i = 0;
int j, k;
int count = 0; // count = 0 "=" peripheral state
int count2; // for '-' operation
while(1){
if(i > Array_Size - 1){ // only monomial can reach this stage
return Calculator_II(Array, Array_Size);
}
if(Array[i] == '(') count ++;
else if(Array[i] == ')') count --;
else if(count == 0 &&
(Array[i] == '+' || Array[i] == '-')){ // only polynomial can reach this stage
if(Array[i] == '+'){
char Array_2[Array_Size - i - 1]; // number(i+1 ~ Array_Size-1)
for(j = i + 1; j < Array_Size; j++){
Array_2[j - i - 1] = Array[j]; // if j = i + 1, j - i - 1 = 0
}
return Calculator_I(Array, i) + Calculator_I(Array_2, Array_Size - i - 1);
}
else if(Array[i] == '-'){
j = i + 1;
count2 = 0;
while(1){
if(j > Array_Size - 1){ // only 'A-B' can reach this stage
char Array_2[Array_Size - i - 1]; // number(i+1 ~ Array_Size-1)
for(k = i + 1; k < Array_Size; k ++){
Array_2[k - i - 1] = Array[k];
}
return Calculator_I(Array, i) - Calculator_I(Array_2, Array_Size - i - 1);
}
if(Array[j] == '(') count2 ++;
else if(Array[j] == ')') count2 --;
else if(count2 == 0 && Array[j] == '+'){ // only 'A-B+C...' can reach this stage
char Array_2[j - i - 1]; //
number(i+1 ~ j-1)
char Array_3[Array_Size - j - 1]; // number(j+1 ~ Array_Size-1)
for(k = i + 1; k < j; k ++){
Array_2[k - i - 1] = Array[k];
}
for(k = j + 1; k < Array_Size; k ++){
Array_3[k - j - 1] = Array[k];
}
return Calculator_I(Array, i) - Calculator_I(Array_2, j - i - 1)
+ Calculator_I(Array_3, Array_Size - j - 1);
}
j ++;
}
char Array_2[Array_Size - i - 1 + 2]; // '2' indicates '(-1)' and '*'
Array_2[0] = '0' - 1;
Array_2[1] = '*';
for(j = i + 1; j < Array_Size; j ++){
Array_2[j - i - 1 + 2] = Array[j];
}
return Calculator_I(Array, i) + Calculator_I(Array_2, Array_Size - i - 1 + 2);
}
}
i ++;
}
}
int Calculator_II(char *Array, int Array_Size){
int i = 0;
int j, k;
int count = 0; // count = 0 "=" peripheral state
while(1){
if(i > Array_Size - 1){ // only '()' or number can reach this stage
if(Array[0] == '('){ // (---) → ---
char Array_2[Array_Size - 2];
for(j = 1; j <= Array_Size - 2; j ++){
Array_2[j - 1] = Array[j];
}
return Calculator_I(Array_2, Array_Size - 2);
}
int test = 1; // only number can reach this stage
int test2 = 0; // below commands print the number as it is
for(j = 0; j < Array_Size - 1; j ++) test *= 10;
for(j = 0; j < Array_Size; j ++){
test2 += (Array[j] - '0') * test;
test /= 10;
}
return test2;
}
if(Array[i] == '(') count ++;
else if(Array[i] == ')') count --;
else if(count == 0 && Array[i] == '*'){ // only 'A*B...' can reach this stage
char Array_2[Array_Size - i - 1]; // number(i+1 ~ Array_Size-1)
for(j = i + 1; j < Array_Size; j ++){
Array_2[j - i - 1] = Array[j]; // if j = i + 1, j - i - 1 = 0
}
return Calculator_I(Array, i) * Calculator_I(Array_2, Array_Size - i - 1);
}
else if(count == 0 && Array[i] == '/'){
j = i + 1;
while(1){
if(j > Array_Size - 1){ // only 'A/B' can reach this stage
char Array_2[Array_Size - i - 1];
// number(i+1 ~ Array_Size-1)
for(k = i + 1; k < Array_Size; k ++){
Array_2[k - i - 1] = Array[k];
}
return Calculator_I(Array, i) / Calculator_I(Array_2, Array_Size - i - 1);
}
if(Array[j] == '*'){ // only 'A/B*C...' can reach this stage
char Array_2[j - i - 1]; // number(i+1 ~ j-1)
char Array_3[Array_Size - j - 1]; // number(j+1 ~ Array_Size-1)
for(k = i + 1; k < j; k ++){
Array_2[k - i - 1] = Array[k];
}
for(k = j + 1; k < Array_Size; k ++){
Array_3[k - j - 1] = Array[k];
}
return Calculator_I(Array, i) / Calculator_I(Array_2, j - i - 1)
* Calculator_I(Array_3, Array_Size - j - 1);
}
j ++;
}
}
i ++;
}
}
int main(int argc, char *argv[]) {
char Array[Max];
int i;
scanf("%s", Array);
for(i = 0; 1; i ++){
if(Array[i] == 0) break;
}
printf("%d", Calculator_I(Array, i)); // number(1 ~ i-1)
return 0;
}
Input: 2013.07.11 21:52
Modified: 2023.06.16 11:46