I am trying to make a reverse Polish printer which can perform the following operation-
Inputs:
(a+(b*c))
((a+b)*(z+x))
((a+t)*((b+(a+c))^(c+d)))
Outputs:
abc*+
ab+zx+*
at+bac++cd+^*
This is my code:
#include <stdio.h>
#include <string.h>
char pop(int t);
void push(int c, int t);
int main()
{
int z;
scanf("%d", &z);
char *a[100];
int i = 0;
int q = z;
while (q-- > 0)
{
char v[400];
scanf("%s", &v);
int t;
for (t = 0; t < strlen(v); t++) //loop to put the values and signs in the 2 stacks
{
if ((v[t] == '*') || (v[t] == '+') || (v[t] == '-') || (v[t] == '^'))
{
push(v[t], 2);
}
else if (v[t] == ')')
{
int y = pop(2);
push(y, 1);
}
else
{
push(v[t], 1);
}
}
int k = 0;
char c;
while ((c = pop(1)) !='\0') //loop to put elements in the array v
{
if (c != '(')
{
v[k++] = c;
}
}
v[k--] = '\0';
int m;
for (m=0; m != k; m++, k--) //for reversing the string
{
char t = v[m];
v[m] = v[k];
v[k] = t;
}
a[i++] =v;
printf("%s",a[i - 1]);
}
int p;
for (p = 0; p <z ; p++) //printing the elements
printf("%s\n",*a[p]);
return 0;
}
char ac[400];
char as[400];
int ic = 0;
int is = 0;
void push(int c,int t)
{
if (t == 1 && ic != 400)
ac[ic++] = c;
else if (t == 2 && is != 400)
as[is++] = c;
}
char pop(int t)
{
if (t == 1 && ic != 0)
return ac[--ic];
if (t == 2 && is != 0)
return as[--is];
return '\0';
}
But it is not even inputting properly and I am not able to figure out what are the mistakes in this code.Please help to figure out what are the problems.
after inputing the no of test cases i.e.int z and first line if input
it crashes
This is due to the
printf("%s\n",*a[p]);
as BLUEPIXY noticed, *a[p] is a char; but %s expects a char *, thus you need
printf("%s\n", a[p]);
and regarding v is out of scope, the crucial factor is not the scope (visibility), but the storage duration (lifetime) of v - its lifetime ends when execution of the block with which it is associated ends, and the value of a pointer a[i] to it becomes indeterminate; by changing
a[i++] =v;
to
a[i++] = strdup(v);
you can remedy that.
Related
I tried to make calculator supporting brackets, but
I have no idea how to deal if the user's input includes expression with spaces, for example:
input: (2 + 3) * 2
i got: 2
If it's normally get (2+3)*2, it counts 10
.
My code:
#include <stdio.h>
#define MAX_SIZE 1024
int insert_operand(int *operand, int * top_num, int num) /* data is pushed into the data stack*/
{
(*top_num) ++;
operand[*top_num] = num; /*save data*/
return 0; /*Exit normally*/
}
int insert_oper (char * oper , int *top_oper , char ch)
{
(*top_oper)++;
oper[*top_oper] = ch; /*save operator*/
return 0; /*Exit normally*/
}
int compare(char *oper , int *top_oper , char ch) /* compare the priority of the operating server*/
{
if((oper[*top_oper] == '-' || oper[*top_oper] == '+') /*Determine whether the current priority is higher than the priority of the operator at the top of the stack*/
&& (ch == '*' || ch == '/'))
{
return 0;
}
else if(*top_oper == -1 || ch == '('
|| (oper[*top_oper] == '(' && ch != ')')) /*Determine whether the operator stack is empty; whether the top operator is '('*/
{
return 0;
}
else if (oper[*top_oper] =='(' && ch == ')')
{
(*top_oper)--;
return 1;
}
else
{
return -1; /*Operate the operator*/
}
}
int deal_date(int *operand ,char *oper ,int *top_num, int *top_oper) /*perform data operation*/
{
int num_1 = operand[*top_num]; /*Take out two data from the data stack*/
int num_2 = operand[*top_num - 1];
int value = 0;
if(oper[*top_oper] == '+')
{
value = num_1 + num_2;
}
else if(oper[*top_oper] == '-')
{
value = num_2 - num_1;
}
else if(oper[*top_oper] == '*')
{
value = num_2 * num_1;
}
else if(oper[*top_oper] == '/')
{
value = num_2 / num_1;
}
(*top_num) --; /*Move the top of the data stack down one bit*/
operand[*top_num] = value; /*Push the obtained value into the data stack*/
(*top_oper) --; /*Move the top of the operator stack down one bit*/
}
int main()
{
int operand[MAX_SIZE] = {0}; /*data stack, initialize*/
int top_num = -1;
char oper[MAX_SIZE] = {0}; /*operator stack, initialize*/
int top_oper = -1;
char *str = (char *) malloc (sizeof(char) * 100); /*get expression (without ＝)*/
scanf("%s", str);
char* temp;
char dest[MAX_SIZE];
int num = 0;
int i = 0;
while(*str != '\0')
{
temp = dest;
while(*str >= '0' && *str <= '9') /*judging whether it is data*/
{
*temp = *str;
str++;
temp++;
} /*Encounter a symbol to exit*/
if(*str != '(' && *(temp - 1) != '\0') /*Determine whether the symbol is '('*/
{
*temp = '\0';
num = atoi(dest); /*convert string to number*/
insert_operand(operand, &top_num,num); /*Push data into the data stack*/
}
while(1)
{
i = compare(oper,&top_oper,*str); /*judgment operator priority*/
if(i == 0)
{
insert_oper(oper,&top_oper,*str); /*press operator*/
break;
}
else if(i == 1) /*judging whether the expression in brackets ends*/
{
str++;
}
else if(i == -1) /* data processing */
{
deal_date(operand,oper,&top_num,&top_oper);
}
}
`
str ++; /* point to the next character of the expression */
}
`
printf("%d\n",operand[0]); /*output result*/
return 0;
I tried to count the equation even if there is a space in it. Can someone please help?
Solving the problem by removing spaces:
So if you're working with equation as string you can simply remove spaces with function like this (there will be probably better way or function in library string.h but this was first guess):
char* DeleteSpaces( char* stringWithSpaces, size_t lengthOfString)
{
char* stringWithoutSpaces = (char*)calloc(lengthOfString + 1, sizeof(char));
if( !stringWithoutSpaces )
return NULL;
for( unsigned int x = 0, y = 0; x <= lengthOfString; x++, y++ )
{
if( stringWithSpaces[x] == ' ' ) // if the character is space
{
while( stringWithSpaces[x] == ' ' && x < lengthOfString ) // skip all the spaces OR go away before you hit '\0'
x++;
stringWithoutSpaces[y] = stringWithSpaces[x]; // then copy next character into new string
}
else // if there's no space just copy the character
stringWithoutSpaces[y] = stringWithSpaces[x];
}
return stringWithoutSpaces;
}
This will basically remove all spaces from your received equation. If you really need the smallest possible memory requirement you can use realloc() at the end of the function for more optimal memory usage.
Here's simple example of how to use the function so you can test it:
int main()
{
char firstString[] = "H e l l o w o r l d\0";
char* secondString;
secondString = DeleteSpaces( firstString, strlen(firstString) );
if( !secondString )
return -1;
printf( "%s", secondString );
free( secondString );
return 0;
}
Don't forget to use free(SecondString). I hope I helped you atleast a little :)
As with the previous answer, I added in a function to remove any spaces from the entered formula in order to process the requested calculation. Also, coupled with that, I revised the "scanf" input to read in all of the entered characters which looked to be another symptom you were facing. With that, following is a refactored version of your program with the additional space compression function.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_SIZE 1024
int insert_operand(int *operand, int * top_num, int num) /* data is pushed into the data stack*/
{
(*top_num) ++;
operand[*top_num] = num; /*save data*/
return 0; /*Exit normally*/
}
int insert_oper (char * oper , int *top_oper , char ch)
{
(*top_oper)++;
oper[*top_oper] = ch; /*save operator*/
return 0; /*Exit normally*/
}
int compare(char *oper , int *top_oper , char ch) /* compare the priority of the operating server*/
{
if((oper[*top_oper] == '-' || oper[*top_oper] == '+') /*Determine whether the current priority is higher than the priority of the operator at the top of the stack*/
&& (ch == '*' || ch == '/'))
{
return 0;
}
else if(*top_oper == -1 || ch == '('
|| (oper[*top_oper] == '(' && ch != ')')) /*Determine whether the operator stack is empty; whether the top operator is '('*/
{
return 0;
}
else if (oper[*top_oper] =='(' && ch == ')')
{
(*top_oper)--;
return 1;
}
else
{
return -1; /*Operate the operator*/
}
}
int deal_date(int *operand ,char *oper ,int *top_num, int *top_oper) /*perform data operation*/
{
int num_1 = operand[*top_num]; /*Take out two data from the data stack*/
int num_2 = operand[*top_num - 1];
int value = 0;
if(oper[*top_oper] == '+')
{
value = num_1 + num_2;
}
else if(oper[*top_oper] == '-')
{
value = num_2 - num_1;
}
else if(oper[*top_oper] == '*')
{
value = num_2 * num_1;
}
else if(oper[*top_oper] == '/')
{
value = num_2 / num_1;
}
(*top_num) --; /*Move the top of the data stack down one bit*/
operand[*top_num] = value; /*Push the obtained value into the data stack*/
(*top_oper) --; /*Move the top of the operator stack down one bit*/
return value;
}
void compress(char *stx) /* The additional function */
{
char work[101];
int i = strlen(stx);
strcpy(work, stx);
for (int j = 0; j < i; j++)
{
stx[j] = 0;
}
i = 0;
for (int j = 0; j < (int)strlen(work); j++)
{
if (work[j] != ' ')
{
stx[i] = work[j];
i++;
}
}
}
int main()
{
int operand[MAX_SIZE] = {0}; /*data stack, initialize*/
int top_num = -1;
char oper[MAX_SIZE] = {0}; /*operator stack, initialize*/
int top_oper = -1;
char *str = (char *) malloc (sizeof(char) * 100); /*get expression (without ＝)*/
//scanf("%s", str);
scanf("%[^\n]", str); /* Refined the scanf call to receive all characters prior to the newline/return character */
compress(str); /* Added this function to remove spaces */
char* temp;
char dest[MAX_SIZE];
int num = 0;
int i = 0;
while(*str != '\0')
{
temp = dest;
while(*str >= '0' && *str <= '9') /*judging whether it is data*/
{
*temp = *str;
str++;
temp++;
} /*Encounter a symbol to exit*/
if(*str != '(' && *(temp - 1) != '\0') /*Determine whether the symbol is '('*/
{
*temp = '\0';
num = atoi(dest); /*convert string to number*/
insert_operand(operand, &top_num,num); /*Push data into the data stack*/
}
while(1)
{
i = compare(oper,&top_oper,*str); /*judgment operator priority*/
if(i == 0)
{
insert_oper(oper,&top_oper,*str); /*press operator*/
break;
}
else if(i == 1) /*judging whether the expression in brackets ends*/
{
str++;
}
else if(i == -1) /* data processing */
{
deal_date(operand,oper,&top_num,&top_oper);
}
}
str ++; /* point to the next character of the expression */
}
printf("%d\n",operand[0]); /*output result*/
return 0;
}
Testing out your sample formula with some additional spacing to ensure the compression function was working properly, following was the terminal output.
#Vera:~/C_Programs/Console/Calculate/bin/Release$ ./Calculate
(2 + 3) * 2
10
Give that a try and see if it meets the spirit of your project.
As pointed out in the comments and other answers, the solution may be to simply "compact" the spaces out of the string before trying to analyse the string's content.
This doesn't require a lot of code:
#include <stdio.h>
char *stripSP( char *src ) {
for( char *d = src, *s = src; ( *d = *s ) != '\0'; s++ )
d += *d != ' ';
return src;
}
int main( void ) {
char *s[] = { "Hello", "H e l l ooo", "(2 + 5) * 3" };
for( int i = 0; i < 3; i++ ) {
printf( "From '%s' ", s[i] );
printf( "'%s'\n", stripSP( s[i] ) );
}
return 0;
}
From 'Hello' 'Hello'
From 'H e l l ooo' 'Hellooo'
From '(2 + 5) * 3' '(2+5)*3'
Even more compact would be to use array indexing:
char *stripSP( char s[] ) {
for( int f=0, t=0; (s[t] = s[f++]) != '\0'; t += s[t] != ' ' ) {}
return s;
}
I want to write a program that will take an input T. In the next T lines, each line will take a string as an input. The output would be how many ways the string can be reordered.
#include <stdio.h>
#include <stdlib.h>
int main() {
int T, i, l, count = 1, test = 0, word = 0, ans;
char line[200];
scanf("%d", &T);
for (i = 0; i < T; i++) {
scanf(" %[^\n]", line);
l = strlen(line);
for (int q = 0; q < l; q++) {
if (line[q] == ' ') {
word++;
}
}
ans = fact(word + 1);
word = 0;
for (int j = 0; j < l; j++) {
for (int k = j + 1; k < l; k++) {
if (line[k] == ' ' && line[k + 1] == line[j]) {
int m = j;
int n = k + 1;
for (;;) {
if (line[m] != line[n]) {
break;
} else
if (line[m] == ' ' && line[n] == ' ') {
test = 1;
break;
} else {
m++;
n++;
}
}
if (test == 1) {
count++;
ans = ans / fact(count);
count = 0;
test = 0;
}
}
}
}
printf("%d\n", ans);
}
}
int fact(int n) {
if (n == 1) {
return 1;
} else {
return n * fact(n - 1);
}
}
Now, in my program,
my output is like this:
2
no way no good
12
yes no yes yes no
120
if T = 2 and the 1st string is no way no good, it gives the right output that is 12 (4!/2!). That means, it has identified that there are two similar words.
But in the 2nd input, the string is yes no yes yes no. that means 3 yes and 2 nos. So the and should be 5!/(3!2!) = 10. But why is the answer 120? and why can't it recognize the similar words?
The main problem in your duplicate detector is you test the end of word with if (line[m] == ' ' && line[n] == ' ') but this test fails to identify a duplicate that occurs with the last word because line[n] is '\0', not ' '.
Note these further problems:
you do not handle words that occur more than twice correctly: you should perform ans = ans / fact(count); only after the outer loop finishes. For example, if a word is present 3 times, it will be detected as 3 pairs of duplicates, effectively causing ans to be divided by 23 = 8, instead of 3! = 6.
you should protect against buffer overflow and detect invalid input with:
if (scanf(" %199[^\n]", line) != 1)
break;
the range of type int for ans is too small for a moderately large number of words: 13! is 6227020800, larger than INT_MAX on most systems.
The code is difficult to follow. You should consider parsing the line into an array of words and using a more conventional way of counting duplicates.
Here is a modified version using this approach:
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static int cmpstr(const void *p1, const void *p2) {
char * const *pp1 = p1;
char * const *pp2 = p2;
return strcmp(*pp1, *pp2);
}
unsigned long long factorial(int n) {
unsigned long long res = 1;
while (n > 1)
res *= n--;
return res;
}
int main() {
int T, i, n, begin, count;
unsigned long long ans;
char line[200];
char *words[100];
if (!fgets(line, sizeof line, stdin) || sscanf(line, "%d", &T) != 1)
return 1;
while (T --> 0) {
if (!fgets(line, sizeof line, stdin))
break;
n = 0;
begin = 1;
for (char *p = line; *p; p++) {
if (isspace((unsigned char)*p)) {
*p = '\0';
begin = 1;
} else {
if (begin) {
words[n++] = p;
begin = 0;
}
}
}
qsort(words, n, sizeof(*words), cmpstr);
ans = factorial(n);
for (i = 0; i < n; i += count) {
for (count = 1; i + count < n && !strcmp(words[i], words[i + count]); count++)
continue;
ans /= factorial(count);
}
printf("%llu\n", ans);
}
return 0;
}
This is supposed to be a Two-Way insertion sort, but it's not sorting. I'm also supposed to print out the number of assignments for sorting, but right now I just want it to sort.
A separate output array of size 2n+1 is set aside. Initially x[0] is placed into the middle element of the array n.
Continue inserting elements until you need to insert between a pair of elements in the array.
As before you need to make room for the new element by shifting elements. Unlike before,
you can choose to shift all smaller elements one step to the left or all larger elements one step
to the right since there is additional room on both sides of the array. The choice of which
shift to perform depends on which would require shifting the smallest amount of elements.
I can't find much on the internet about this sort except that no one uses it.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void printArray(int arr[], int len) {
for (int j = 0; j < len; j++)
printf("%d ", arr[j]);
printf("\n");
}
int main() {
FILE *in;
int size_arr = 0;
char ch;
if ((in = fopen("data_a5.txt", "r")) == NULL) {
printf("Error!");
exit(1);
}
do {
ch = fgetc(in);
if (ch == '\n')
size_arr++;
} while (ch != EOF);
rewind(in);
int arr[size_arr];
int sort_arr[2 * size_arr + 1];
int n = 0;
while (!feof(in)) {
fscanf(in, "%d", &arr[n]);
n++;
}
fclose(in);
for (n = 0; n < 2 * size_arr; n++) {
sort_arr[n] = 0;
}
sort_arr[size_arr] = arr[0];
for (n = 1; n < size_arr; n++) {
int index = size_arr;
if (arr[n] <= sort_arr[size_arr]) {
while (!(arr[n] <= sort_arr[index]) && sort_arr[index] != 0 && index >= 0) {
index--;
}
}
if (arr[n] > sort_arr[size_arr]) {
while (!(arr[n] <= sort_arr[index]) && sort_arr[index] != 0 && index < 2 * size_arr) {
index++;
}
}
if (sort_arr[index] == 0) {
sort_arr[index] = arr[n];
} else {
int next_R, next_L = index;
while (sort_arr[next_R] != 0 && next_R <= 2 * size_arr) {
next_R++;
}
while (sort_arr[next_L] != 0 && next_L >= 0) {
next_L--;
}
int R_move = next_R - index;
int L_move = index - next_L;
if (R_move > L_move) {
while (L_move <= index) {
sort_arr[L_move] = sort_arr[L_move + 1];
L_move++;
}
sort_arr[index] = arr[n];
} else {
while (R_move >= index) {
sort_arr[R_move] = sort_arr[R_move - 1];
R_move--;
}
sort_arr[index] = arr[n];
}
}
}
printArray(arr, size_arr);
return 0;
}
I'm not sure this solves all problems but it is a problem you must fix.
This code
int next_R, next_L = index;
while(sort_arr[next_R] != 0 && next_R <= 2*size_arr)
has undefined behavior as next_R is uninitialized.
Maybe you want:
int next_R = index, next_L = index;
^^^^^
while(sort_arr[next_R] != 0 && next_R <= 2*size_arr)
In any case you have to initialize next_R before using it.
I also find this line strange:
printArray(arr, size_arr);
^^^
Seems you are printing the original array instead of the sorted array.
May be you want:
printArray(sort_arr, size_arr);
^^^^^
There are some problems in your code:
when you scan the file in the first pass, you should count the number of integers instead of the number of characters.
when inserting, your loops are off by one: the tests should read while (L_move < index) and while (R_move >= index)
while (!feof(in)) is always wrong, you should instead write while (fscanf(in, "%d", &arr[n]) == 1) {...
you should probably allocate the arrays arr and sort_arr instead of defining them as VLAs with automatic storage to prevent undefined behavior on large input files.
you should use binary search into the sorted portion, otherwise your algorithm has a basic complexity of O(N2) that dwarfs the small gain obtained from the minimisation of the insertion phase.
Here is the code:
#include <stdio.h>
#include <stdlib.h>
void print_array(const int arr[], int len) {
for (int j = 0; j < len; j++)
printf("%d%c", arr[j], " \n"[j == len - 1]);
}
int main(void) {
FILE *in;
int size_arr, n, start;
int value;
if ((in = fopen("data_a5.txt", "r")) == NULL) {
printf("Cannot open input file %s\n", "data_a5.txt");
exit(1);
}
for (size_arr = 0; fscanf(in, "%d", &value) == 1; size_arr++)
continue;
rewind(in);
int *arr = calloc(2 * size_arr + 1, sizeof(*arr));
if (arr == NULL) {
printf("Cannot allocate memory for %d entries\n", size_arr);
exit(1);
}
start = size_arr;
for (n = 0; n < size_arr && fscanf(in, "%d", &value) == 1; n++) {
/* insert value into the sorted array */
int a, b;
for (a = start, b = start + n; a < b;) {
int mid = a + (b - a) / 2;
if (arr[mid] < value) {
a = mid + 1;
} else {
b = mid;
}
}
/* insert value at offset b */
if (b - start < start + n - b) {
/* shift left portion to the left */
for (int i = start--; i < b; i++) {
arr[i - 1] = arr[i];
}
b--;
} else {
/* shift right portion to the right */
for (int i = start + n + 1; --i > b;) {
arr[i] = arr[i - 1];
}
}
arr[b] = value;
}
fclose(in);
print_array(arr + start, n);
free(arr);
return 0;
}
like this
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void printArray(int arr[], int len){
while(len--)
printf("%d ", *arr++);
printf("\n");
}
int main(void){
int size_arr = 10;
int arr[size_arr];
int sort_arr[2 * size_arr + 1];
for(int i = 0; i < size_arr; ++i)
arr[i] = -50 + rand() % (100 + 1);
puts("before:");
printArray(arr, size_arr);
int left, right;
sort_arr[left = right = size_arr] = arr[0];
for (int n = 1; n < size_arr; ++n){
int v = arr[n];
if(v <= sort_arr[left]){
sort_arr[--left] = v;
} else if(v >= sort_arr[right]){
sort_arr[++right] = v;
} else {
int L = left, R = right, M, MV;
while(L <= R){
M = L + (R-L)/2;
MV = sort_arr[M];
if(MV < v)
L = M + 1;
else if(v < MV)
R = M - 1;
else
break;
}
//M: insert position
enum { LEFT, RIGHT } CHOICE;
if(v == MV){
int ML = M, MR = M;
while(sort_arr[ML-1] == sort_arr[ML])
--ML;
while(sort_arr[MR] == sort_arr[MR+1])
++MR;
if( ML-left >= right-MR){
M = MR+1;
CHOICE = RIGHT;
} else {
M = ML;
CHOICE = LEFT;
}
} else if(v > MV){
++M;
CHOICE = M-left+1 > right-M;// ? RIGHT : LEFT;
} else {
CHOICE = M-left-1 > right-M;// ? RIGHT : LEFT;
}
if(CHOICE == RIGHT){
memmove(sort_arr + M+1, sort_arr + M, (right-M+1)*sizeof(v));
sort_arr[M] = v;
++right;
} else {
memmove(sort_arr + left-1, sort_arr + left, (M-left)*sizeof(v));
sort_arr[M-1] = v;
--left;
}
}
}
puts("after:");
printArray(sort_arr + left, size_arr);
return 0;
}
I'm doing a shift-reduce algorithm for our compiler design subject. This is the code.
void shiftReduce(char str[MAX_CHAR], int prodNum, int line)
{
int limit = 5, y=0;
int substrFlag = 1; //0 true 1 false
int ctr,x, counter;
int match, next;
char stack[MAX_CHAR];
clearString(stack);
OUTER:while ((strcmp(stack, prod[0].left) != 0) && (y < limit))
{
addChar(stack, str[0]);
strcpy(str, dequeue(str));
printf("Stack = %s\nQueue = %s\n", stack, str);
for (ctr = 0; ctr < prodNum; ctr++)
{
if (strstr(stack, prod[ctr].right) != NULL)
{ //substring found
substrFlag = 0;
strcpy(stack, replace(stack, prod[ctr].right, prod[ctr].left));
goto OUTER;
}
}
if ((str[0] == '\n') || (str[0] == '\0'))
y++;
}
if (strcmp(stack, prod[0].left) == 0)
;//printf("%s - Accepted.\n", stack);
else
printf("Syntax error on line %i\n", line);
}
When I comment the printf("Stack = %s\nQueue = %s\n", stack, str); line, it works well. But when I uncomment it, it returns the code 3221225477.
BTW. This is the dequeue function:
char * dequeue (char str[MAX_CHAR])
{
int x = 0; char temp;
for (x = 0; x < length(str); x++)
{
if ((x+1) < length(str))
str[x] = str[x+1];
}
return str;
}
and the addChar function:
void addChar (char * str, char letter)
{
int a = 0;
while (str[a] != '\0')
a++;
str[a] = letter;
str[a+1] = '\0';
return;
}
and finally replace function.
char * replace (char orig[MAX_CHAR], char substr[MAX_CHAR], char rep[MAX_CHAR])
{
int match, end=0, next=0;
int flag = 0; //0 true 1 false
char temp [MAX_CHAR];
char store[MAX_CHAR];
if (strstr(orig, substr) == NULL)
return NULL;
int x,y;
for (x = 0; x < length(orig); x++)
{
if (orig[x] == substr[0]) //if current character is equal to first character of substring
{
match = x;
for (y = 0; y < length(substr); y++)
{
if (orig[match+y] != substr[y])
{
flag = 1;
break;
}
}
if (flag == 0)
{
next = match + length(substr);
for (y = 0; y < length(rep); y++)
{
temp[match+y] = rep[y];
end = (match+y);
}
for (y = next; y < length(orig); y++)
{
temp[y] = orig[next+(y-next)];
}
return temp;
}
}
else
{
addChar(temp, orig[x]);
}
}
return temp;
}
PS. The prod array:
struct RULES
{
char left[MAX_CHAR];
char right[MAX_CHAR];
} RULES;
struct RULES prod[MAX_RULES];
When I comment the printf("Stack = %s\nQueue = %s\n", stack, str); line, it works well. But when I uncomment it, it returns the code 3221225477.
Then most likely either stack or str has not been 0-terminated or points to invalid memory.
I am trying to make a reverse Polish printer on an online coding website which can perform the following operation-
Inputs:
(a+(b*c))
((a+b)*(z+x))
((a+t)*((b+(a+c))^(c+d)))
Outputs:
abc*+
ab+zx+*
at+bac++cd+^*
This is my code:
#include <stdio.h>
#include <string.h>
char pop(int t);
void push(int c, int t);
char a[100][400];
int main()
{
int z;
scanf("%d", &z);
int i = 0;
int q = z;
while (q-- > 0)
{
scanf("%s",&a[i][0]);
int t;
for (t = 0; t < strlen(a[i]); t++) //loop to put the values and signs in the 2 stacks
{
if ((a[i][t] == '*') || (a[i][t] == '+') || (a[i][t] == '-') || (a[i][t] == '^'))
{
push(a[i][t], 2);
}
else if (a[i][t] == ')')
{
int y = pop(2);
push(y, 1);
}
else
{
push(a[i][t], 1);
}
}
int k = 0;
char c;
while ((c = pop(1)) !='\0') //loop to put elements in the array v
{
if (c != '(')
{
a[i][k++] = c;
}
}
a[i][k--] = '\0';
int m;
for (m=0; m != k; m++, k--)
{
char t = a[i][m];
a[i][m] = a[i][k];
a[i][k] = t;
}
}
int p;
for (p = 0; p <z ; p++)
printf("%s\n",a[i]);
return 0;
}
char ac[400];
char as[400];
int ic = 0;
int is = 0;
void push(int c,int t)
{
if (t == 1 && ic != 400)
ac[ic++] = c;
else if (t == 2 && is != 400)
as[is++] = c;
}
char pop(int t)
{
if (t == 1 && ic != 0)
return ac[--ic];
if (t == 2 && is != 0)
return as[--is];
return '\0';
}
On compiling this code I am getting a SIGSEGV error.I don't know whats the mistake in this code.Please help
I don't know why you are getting SIGSEGV. However, I see couple of errors in your code.
You are using scanf("%s",&a[i][0]); but i is never changed from its initial value of 0. I suggest changing
while (q-- > 0)
to
for ( i = 0; i < z; ++i )
You are printing a[i] even though you are using p as the for loop index in
for (p = 0; p <z ; p++)
printf("%s\n",a[i]);
That's easily fixed by changing the second line to:
printf("%s\n",a[p]);
In your input, you didn't include the value of z. I hope that is an error in creating the post and that you have the value of z in your input.
With those changes, I don't see any problem in my environment. I tested using gcc 4.7.3. Not sure fixing those will fix the problem in your environment.