我需要使用getchar（），putchar（）进行I / O.我的程序运行得很好，但我不能像在CodeWarrior中那样使用嵌入式系统。我还需要摆脱malloc（）并使用堆栈进行pop / push。如果我不再使用scanf，我还可以使用strtol吗？
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX 10
float *p, *tos, *bos;
int *p2, *tos2, *bos2;
int imode = 1;
void push(float f); float pop(void);
void push2(int i); int pop2(void);
int main (void) {
float a, b;
int c, d;
char s[64];
// p = malloc ( MAX * sizeof *p );
p = (float *) malloc(MAX*sizeof(float)); /* get stack memory */
p2 = (int *) malloc(MAX*sizeof(int)); /* get stack memory */
if (!p || !p2) {
printf("Allocation Failure\n");
exit(1);
}
tos = p; bos = p + MAX-1;
tos2 = p2; bos2 = p2 + MAX-1;
printf("\nRPN Calculator\n");
printf("Enter 'i' for Integer mode (default)\n");
printf("Enter 'f' for Floating point mode\n");
printf("Enter 'm' to Show Menu\n");
printf("Enter 'q' to Quit\n\n");
char *endptr;
do {
printf("> ");
scanf("%s", s);
if (imode == 0) { /* Floating Mode */
float val = strtof(s, &endptr); /* string to float conversion */
if (*endptr == '\0') {
//printf("Got only the floateger: %d\n", val);
}
else {
//printf("operator: %s\n", endptr);
//printf("float: %f\n", val);
if (val != 0){ /* don't push val on stack if 0 */
push(val);
}
}
switch(*endptr) {
case 'i':
printf("\n (Integer Mode)\n");
imode = 1; /* mode flag */
break;
case 'f':
printf("\n (Floating Point Mode)\n");
imode = 0; /* mode flag */
break;
case 'm':
printf("\nRPN Calculator\n");
printf("Enter 'i' for Integer mode\n");
printf("Enter 'f' for Floating point mode\n");
printf("Enter 'm' to Show Menu\n");
printf("Enter 'q' to Quit\n\n");
break;
case '+':
a = pop(); b = pop();
printf("= %f\n",a+b);
push(a+b);
break;
case '-':
a = pop(); b = pop();
printf("= %f\n", b-a);
push(b-a);
break;
case '*':
a = pop(); b = pop();
printf("= %f\n", a*b);
push(a*b);
break;
case '/':
a = pop(); b = pop();
if(a == 0){
printf("Cannot divide by zero\n");
break;
}
printf("= %f\n", b/a);
push(b/a);
break;
case '.':
a = pop(); push(a);
printf("Top of stack value: %f\n", a);
break;
default:
push(val);
}
}
else { /* Integer Mode */
int val2 = strtod(s, &endptr); /* string to float conversion */
if (*endptr == '\0') {
//printf("Got only the floateger: %d\n", val);
}
else {
//printf("operator: %s\n", endptr);
// printf("int: %d\n", val2);
if (val2 != 0){ /* don't push val on stack if 0 */
push2(val2);
}
}
switch(*endptr) {
case 'i':
printf("\n (Integer Mode)\n");
imode = 1; /* mode flag */
break;
case 'f':
printf("\n (Floating Point Mode)\n");
imode = 0; /* mode flag */
break;
case 'm':
printf("\nRPN Calculator\n");
printf("Enter 'i' for Integer mode\n");
printf("Enter 'f' for Floating point mode\n");
printf("Enter 'm' to Show Menu\n");
printf("Enter 'q' to Quit\n\n");
break;
case '+':
c = pop2(); d = pop2();
// printf("%d\n", c);
// printf("%d\n", d);
printf("= %d\n",c+d);
push2(c+d);
break;
case '-':
c = pop2(); d = pop2();
printf("= %d\n", d-c);
push2(d-c);
break;
case '*':
c = pop2(); d = pop2();
printf("= %d\n", c*d);
push2(c*d);
break;
case '/':
c = pop2(); d = pop2();
if(c == 0){
printf("Cannot divide by zero\n");
break;
}
printf("= %d\n", d/c);
push2(d/c);
break;
case '.':
c = pop2(); push2(c);
printf("Top of stack value: %d\n", c);
break;
default:
// push(atoi(s));
push2(val2);
}
}
} while (*s != 'q'); /* Do until 'q' is entered */
return 0;
}
void push (float f) { /* Put an element on the stack */
*p = f;
p++;
}
float pop (void) { /* Get the element from the top of the stack */
p--;
return *p;
}
void push2 (int i) {
*p2 = i;
p2++;
}
int pop2(void) {
p2--;
return *p2;
}
这是我目前为int模式所做的：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX 50
int *p;
int *tos;
int *bos;
void push(int i);
int pop(void);
int main (void)
{
int a, b;
char s[5];
int c;
int count;
tos = p;
bos = p + MAX-1;
printf("\nRPN Calculator\n");
printf("Enter 'i' for integer mode\n");
printf("Enter 'f' for floating point mode\n");
printf("Enter 'q' to quit\n\n");
char *endptr;
do {
printf("> ");
//scanf("%s", s);
count = 0;
while ((count < 5) && (c != EOF) && (c !='\n')) { /* don't go over the array size! */
s[count] = c;
++count;
c = getchar(); /* get another character */
}
//for (c=0; c<count; c++) {
//putchar(c);
//}
int val = strtol(s, &endptr, 10);
if (*endptr == '\0') {
//printf("Got only the integer: %d\n", val);
}
else {
//printf("operator: %s\n", endptr);
//printf("integer: %d\n", val);
if (val != 0){ /* don't push val on stack if 0 */
push(val);
}
}
switch(*endptr) {
case 'i':
printf("(Integer Mode)\n");
break;
case 'f':
printf("(Floating Point Mode)\n");
break;
case '+':
a = pop();
b = pop();
// printf("%d\n",a);
// printf("%d\n",b);
// printf("%d\n",val);
printf("%d\n", a+b);
push(a+b);
break;
case '-':
a = pop();
b = pop();
// printf("%d\n", b-a);
push(b-a);
break;
case '*':
a = pop();
b = pop();
// printf("%d\n", a*b);
push(a*b);
break;
case '/':
a = pop();
b = pop();
if(a == 0){
// printf("Cannot divide by zero\n");
break;
}
// printf("%d\n", b/a);
push(b/a);
break;
case '.':
a = pop(); push(a);
// printf("Current value on top of stack: %d\n", a);
break;
default:
push(val);
}
} while (c != 'q'); /* Do until 'q' is entered */
return 0;
}
void push (int i) /* Put an element on the stack */
{
if (p > bos){
printf("Stack Full\n");
return;
}
*p = i;
p++;
}
int pop (void) /* Get the element from the top of the stack */
{
p--;
if(p < 0) {
printf("Stack Underflow\n");
return 0;
}
return *p;
}
答案 0 :(得分：1)
是否可以使用strtol（）取决于您的嵌入式系统。
C标准识别两种环境。一个是正常的“托管”环境，它为C库提供全面支持。另一种是“独立”环境。这只需要在C：
中为7个标题提供支持<float.h>
<iso646.h>
<limits.h>
<stdarg.h>
<stdbool.h>
<stddef.h>
<stdint.h>
由于您处于嵌入式环境中，因此您可以依赖这些内容。对于其他所有内容，您需要阅读适合您环境的手册。
可以使用strtol（）的可能性很大。