diff options
| -rw-r--r-- | 4/10.c | 94 |
1 files changed, 90 insertions, 4 deletions
@@ -1,9 +1,12 @@ #include <ctype.h> +#include <math.h> #include <stdio.h> +#include <stdlib.h> #include <string.h> #define MAXOP 100 #define MAXLINE 1000 +#define HEIGHT 1000 #define NUM '0' #define FUN '1' @@ -14,9 +17,10 @@ void push(double); double peek(); double pop(); void clear(); +double vartoval(char); int main(int argc, char *argv[]) { - int type; + int type, op1, op2; char s[MAXOP]; printf("Press CTRL+C to exit\n"); @@ -24,16 +28,58 @@ int main(int argc, char *argv[]) { while (type == getop(s)) { switch (type) { case NUM: + push(atof(s)); break; case '+': + op1 = pop(); + op2 = pop(); + if (isalpha(op1)) + op1 = vartoval(op1); + if (isalpha(op2)) + op2 = vartoval(op2); + push(op1 + op2); break; case '-': + op1 = pop(); + op2 = pop(); + if (isalpha(op1)) + op1 = vartoval(op1); + if (isalpha(op2)) + op2 = vartoval(op2); + push(op1 - op2); break; case '*': + op1 = pop(); + op2 = pop(); + if (isalpha(op1)) + op1 = vartoval(op1); + if (isalpha(op2)) + op2 = vartoval(op2); + push(op1 * op2); break; case '/': + op1 = pop(); + op2 = pop(); + if (isalpha(op1)) + op1 = vartoval(op1); + if (isalpha(op2)) + op2 = vartoval(op2); + if (op1 == 0.0) + printf("error: division by zero\n"); + else + push((double)op2 / op1); break; case '%': + op1 = pop(); + op2 = pop(); + if (isalpha(op1)) + op1 = vartoval(op1); + if (isalpha(op2)) + op2 = vartoval(op2); + if (op1 == 0.0) + printf("error: division by zero\n"); + else + push((int)op2 % (int)op1); break; case '=': break; @@ -52,10 +98,10 @@ int line[MAXLINE]; void mgetline() { int i, c; - + for (i = 0; i < MAXLINE - 1 && (c = getchar()) != '\n' && c != EOF; i++) { line[i] = c; - } + } line[i] = 0; ptr = 0; } @@ -66,7 +112,7 @@ int getop(char s[]) { if (line[ptr] == 0) mgetline(); - // get next token + // get next token for (i = 0; i < MAXOP - 1 && (c = line[ptr]) != ' ' && c != 0; i++, ptr++) s[i] = c; s[i] = 0; @@ -81,5 +127,45 @@ int getop(char s[]) { return s[0]; } + if (i > 1 && (isdigit(s[0]) || s[0] == '-' && isdigit(s[1]))) + return NUM; + + // last printed variable + if (strcmp("LOUT", s) == 0) + return VAR; + return FUN; +} + +int sp = 0; +double stack[HEIGHT]; + +void push(double f) { + if (sp < HEIGHT) + stack[sp++] = f; + else + printf("error: stack empty\n"); +} + +double pop() { + if (sp > 0) + return stack[--sp]; + else { + printf("error: stack empty\n"); + return 0.0; + } +} + +double peek() { + if (sp > 0) + return stack[sp - 1]; + else { + printf("error: stack empty\n"); + return 0.0; + } +} + +void clear() { + for (; sp > 0; sp--) + ; }
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