diff options
-rw-r--r-- | ex4-3.c | 129 |
1 files changed, 49 insertions, 80 deletions
@@ -1,9 +1,10 @@ #include <stdio.h> #include <stdlib.h> #include <ctype.h> +#include <string.h> #define NUMBER '0' -#define MAXOP 100 +#define MAXLINE 1000 #define MAXVAL 100 int getop(char[]); @@ -22,48 +23,54 @@ double frem(double f1, double f2) { * Reverse polish notation calculator */ int main(void) { - int type; double op2; - char s[MAXOP]; - while ((type = getop(s)) != EOF) { - switch (type) { - case NUMBER: - push(atof(s)); - break; - case '+': - push(pop() + pop()); - break; - case '*': - push(pop() * pop()); - break; - case '-': - op2 = pop(); - push(pop() - op2); - break; - case '/': - op2 = pop(); - if (op2 != 0.0) - push(pop() / op2); - else - printf("error: zero division attempted!\n"); - break; - case '%': - op2 = pop(); - if (op2 != 0.0) - push(frem(pop(), op2)); - else - printf("error: zero division attempted!\n"); - break; - case '~': - clear(); - case '\n': - printf("\t%.8g\n", peek()); - break; - default: - printf("unknown command %s\n", s); - break; - } + char* line = NULL; + size_t line_len = 0; + while (getline(&line, &line_len, stdin) != -1) { + char* tok = strtok(line, " "); + do { + int type = getop(tok); + switch (type) { + case NUMBER: + push(atof(tok)); + break; + case '+': + push(pop() + pop()); + break; + case '*': + push(pop() * pop()); + break; + case '-': + op2 = pop(); + push(pop() - op2); + break; + case '/': + op2 = pop(); + if (op2 != 0.0) + push(pop() / op2); + else + printf("error: zero division attempted!\n"); + break; + case '%': + op2 = pop(); + if (op2 != 0.0) + push(frem(pop(), op2)); + else + printf("error: zero division attempted!\n"); + break; + case '~': + clear(); + break; + default: + //printf("unknown command %s\n", tok); // Just ignore it? + break; + } + } while ((tok = strtok(NULL, " ")) != NULL); + + printf("\t%.8g\n", pop()); } + free(line); // or, don't bother since we exit the program next... + return 0; } @@ -99,47 +106,9 @@ void clear(void) { sp = 0; } -int getch(void); -void ungetch(int); - int getop(char s[]) { - int i,c; - // Skip to teh first non-space or tab character - while ((s[0] = c = getch()) == ' ' || c == '\t'); - // Then add a null for some reason? - s[1] = '\0'; - // if it's not a part of a number, it's an operation + char c = s[0]; if (!isdigit(c) && c != '.') return c; - // Integer part - i = 0; - if (isdigit(c)) - while (isdigit(s[++i] = c = getch())); - // fraction part - if (c == '.') - while (isdigit(s[++i] = c = getch())); - s[i] = '\0'; - if (c != EOF) - ungetch(c); return NUMBER; } - -#define BUFSIZE 100 - -int buf = -2; - -int getch(void) { - if (buf != -2) { - int z = buf; - buf = -2; - return z; - } - return getchar(); -} - -void ungetch(int c) { - if (buf != -2) - printf("ungetch: buffer full\n"); - else - buf = c; -}
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