K&R Book 3-2 Exercise (escape function) - c

Question

Write a function escape(s,t) that converts characters like newline and
tab into visible escape sequences like \n and \t as it copies the
string t to s. Use a switch. Write a function for the other direction
as well, converting escape sequences into the real characters.
This is the Exercise 3-2 from K&R book. So I tried to do it. My escape function works properly. But my inverseescape is giving me the same answer as the escape function is giving. Here is the code:
#include <stdio.h>
#define MCC 100
void espace(int* str,int* t);
void inverseescape(int * str,int *t);
void getline(int*);
int main(void){
int firstarr[MCC];
int secondarr[MCC];
int thirdarr[MCC];
getline(firstarr);
espace(firstarr,secondarr);
printf("-----------AFTER ESCAPE------------\n");
for(int g=0;secondarr[g];g++){
printf("%c",secondarr[g]);
}
inverseescape(secondarr,thirdarr);
printf("\n-----------AFTER INVERSEESCAPE------------\n");
for(int g=0;thirdarr[g];g++){
printf("%c",thirdarr[g]);
}
return 0;
}
void getline(int* arr){
int i=0;
int c=0;
while((c=getchar())!=EOF){
arr[i]=c;
arr[i+1]=0;
i++;
}
}
void espace(int* string,int* target){
int i = 0;
int j = 0;
while(string[i]){
switch(string[i]){
case '\a':
target[j]='\\';
target[++j]='a';
target[++j]=0;
break;
case '\b':
target[j]='\\';
target[++j]='b';
target[++j]=0;
break;
case '\t':
target[j]='\\';
target[++j]='t';
target[++j]=0;
break;
case '\n':
target[j]='\\';
target[++j]='n';
target[++j]=0;
break;
case '\v':
target[j]='\\';
target[++j]='v';
target[++j]=0;
break;
case '\f':
target[j]='\\';
target[++j]='f';
target[++j]=0;
break;
case '\r':
target[j]='\\';
target[++j]='r';
target[++j]=0;
break;
case '\"':
target[j]='\\';
target[++j]='\"';
target[++j]=0;
break;
case '\'':
target[j]='\\';
target[++j]='\'';
target[++j]=0;
break;
case '\?':
target[j]='\\';
target[++j]='\?';
target[++j]=0;
break;
case '\\':
target[j]='\\';
target[++j]='\\';
target[++j]=0;
break;
default:
target[j]=string[i];
target[++j]=0;
break;
}
i++;
}
}
void inverseescape(int* string,int* target){
int i = 0;
while(string[i]){
switch(string[i]){
case '\\':
switch(string[i+1]){
case 'a':
target[i]='\a';
case 'b':
target[i]='\b';
case 't':
target[i]='\t';
case 'n':
target[i]='\n';
case 'v':
target[i]='\v';
case 'f':
target[i]='\f';
case 'r':
target[i]='\r';
case '\"':
target[i]='\"';
case '\'':
target[i]='\'';
case '\?':
target[i]='\?';
case '\\':
target[i]='\\';
}
default:
target[i]=string[i];
}
target[++i]=0;
}
}
I am using switch statement first time (and probably last) so the code is not well-written (i guess).
Input:
shadow
of
the
beast
Output:
-----------AFTER ESCAPE------------
shadow\nof\nthe\nbeast
-----------AFTER INVERSEESCAPE------------
shadow\nof\nthe\nbeast

Answer 1

You're missing the break in the inverseescape case statement. case's behaviour has the curious property of falling through to the statement below unless you explicitly break out of the case. In this case it's falling through to your default case and setting the output to the input.