Comment puis-je convertir mon code en utilisant getchar() putchar() au lieu d'utiliser scanf() et printf() pour les E/S?

Question

J'ai besoin d'utiliser getchar(), putchar() pour les E/S. Mon programme fonctionne très bien mais je ne peux pas l'utiliser comme dans CodeWarrior pour un système embarqué. Je dois aussi me débarrasser de malloc() et utiliser une pile pour pop/push. Puis-je toujours utiliser strtol si je n'utilise plus scanf?

#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; 
} 

C'est ce que j'ai jusqu'à présent pour le mode int:

#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; 
} 

Answer 1

Que vous pouvez utiliser strtol() ou non dépend de votre système embarqué.

La norme C reconnaît deux environnements. L'un est l'environnement «hébergé» normal, qui fournit un support complet pour la bibliothèque C. L'autre est un environnement «autonome». Cela n'a qu'à soutenir les 7 têtes dans C:

<float.h> 
<iso646.h> 
<limits.h> 
<stdarg.h> 
<stdbool.h> 
<stddef.h> 
<stdint.h> 

Puisque vous êtes dans un environnement intégré, vous pouvez compter sur les 7. Pour tout le reste, vous devez lire le manuel pour votre environnement.

Les chances sont bonnes que vous pouvez utiliser strtol().