diff options
| -rw-r--r-- | 4/5.c | 127 |
1 files changed, 44 insertions, 83 deletions
@@ -2,10 +2,12 @@ #include <math.h> #include <stdio.h> #include <stdlib.h> +#include <string.h> -#define MAXOP 100 /* max size of operand or operator */ -#define NUMBER '0' /* signal that a number was found */ -#define MAXVAL 100 /* max depth of val stack */ +#define MAXOP 100 /* max size of operand or operator */ +#define NUMBER '0' /* signal that a number was found */ +#define FUNCTION '1' /* signal that a custom op was found */ +#define MAXVAL 100 /* max depth of val stack */ #define BUFSIZE 100 int sp = 0; /* next free stack position */ @@ -29,7 +31,7 @@ double peek(); /* clears the stack */ void clear(); -/* adds support sin, exp and power functions */ +/* adds support for sin, exp and pow functions */ int main(int argc, char *argv[]) { int type; double op2, op1; @@ -64,29 +66,26 @@ int main(int argc, char *argv[]) { else printf("error: division by zero\n"); break; - case 'p': - peek(); - break; - case 'c': - push(peek()); - break; - case 's': - op2 = pop(); - op1 = pop(); - push(op2); - push(op1); - break; - case 'd': - clear(); - break; - case 'S': - push(sin(pop())); - break; - case 'P': - push(pow(pop(), pop())); - break; - case 'E': - push(exp(pop())); + case FUNCTION: + if (strcmp("top", s) == 0) + peek(); + else if (strcmp("dup", s) == 0) + push(peek()); + else if (strcmp("swp", s) == 0) { + op2 = pop(); + op1 = pop(); + push(op2); + push(op1); + } else if (strcmp("cls", s) == 0) + clear(); + else if (strcmp("sin", s) == 0) + push(sin(pop())); + else if (strcmp("exp", s) == 0) + push(exp(pop())); + else if (strcmp("pow", s) == 0) + push(pow(pop(), pop())); + else + printf("error: unknown function %s\n", s); break; case '\n': printf("\t%.8g\n", pop()); @@ -139,73 +138,35 @@ void ungetch(int c) { } int getop(char s[]) { - int i, c; + int i, c, rv; while ((s[0] = c = getch()) == ' ' || c == '\t') ; s[1] = 0; - if (!isdigit(c) && c != '.' && c != '-' && c != 's' && c != 'p' && c != 'e') + // operators or line feed + if (c == '\n' || c == '+' || c == '*' || c == '/' || c == '%') return c; i = 0; - if (isdigit(c)) - while (isdigit(s[++i] = c = getch())) - ; - if (c == '.') - while (isdigit(s[++i] = c = getch())) - ; - if (c == '-') - while (isdigit(s[++i] = c = getch())) - ; - // sin or swap function - if (c == 's') { - if ((c = getch()) == ' ') - return 's'; - else if (c == 'i') { - if ((c = getch()) == 'n') { - return 'S'; - } else { - ungetch(c); - ungetch('i'); - return 's'; - } - } else { - ungetch(c); - return 's'; - } - } - // power function - if (c == 'p') { - if ((c = getch()) == 'o') { - if ((c = getch()) == 'w') { - return 'P'; - } else { - ungetch(c); - ungetch('o'); - return 'p'; - } - } else { + // numbers + if (isdigit(c) || c == '-') { + // minus operator + if (c == '-' && !isdigit(s[++i] = c = getch())) { ungetch(c); - return 'p'; + s[i] = 0; + return '-'; } - } - // exponent function - if (c == 'e') { - if ((c = getch()) == 'x') { - if ((c = getch()) == 'p') { - return 'E'; - } else { - ungetch(c); - ungetch('x'); - return 'e'; - } - } else { - ungetch(c); - return 'e'; - } + while (isdigit(s[++i] = c = getch()) || c == '.') + ; + rv = NUMBER; + } else { + // functions + while (isalnum(s[++i] = c = getch())) + ; + rv = FUNCTION; } s[i] = 0; @@ -213,5 +174,5 @@ int getop(char s[]) { if (c != EOF) ungetch(c); - return NUMBER; + return rv; } |