SHOW:
|
|
- or go back to the newest paste.
| 1 | #include<stdio.h> | |
| 2 | #include<string.h> | |
| 3 | #include<ctype.h> | |
| 4 | #define MAX 100 | |
| 5 | ||
| 6 | typedef struct | |
| 7 | {
| |
| 8 | char s[MAX]; // Operator Stack | |
| 9 | char a[MAX]; //Infix Expression | |
| 10 | char b[MAX]; //Postfix Expression | |
| 11 | int tos; //Top of stack | |
| 12 | int postindex; //Index of Postfix. Don't ask why defined here. Just feeling like it :P | |
| 13 | }infix; | |
| 14 | ||
| 15 | void transfer(infix *t,char k) | |
| 16 | {
| |
| 17 | t->b[t->postindex]=k; | |
| 18 | t->postindex++; | |
| 19 | } | |
| 20 | ||
| 21 | int ipr(char a) | |
| 22 | {
| |
| 23 | if (a=='(')
| |
| 24 | return 3; | |
| 25 | else if (a=='+'||a=='-') | |
| 26 | return 1; | |
| 27 | else if (a=='%'||a=='/'||a=='*') | |
| 28 | return 2; | |
| 29 | } | |
| 30 | ||
| 31 | int rpr(char a) | |
| 32 | {
| |
| 33 | if (a=='(')
| |
| 34 | return 0; | |
| 35 | else if (a=='+'||a=='-') | |
| 36 | return 1; | |
| 37 | else if (a=='%'||a=='/'||a=='*') | |
| 38 | return 2; | |
| 39 | } | |
| 40 | ||
| 41 | int isempty(infix *t) | |
| 42 | {
| |
| 43 | if (t->tos==-1) | |
| 44 | return 1; | |
| 45 | else | |
| 46 | return 0; | |
| 47 | } | |
| 48 | ||
| 49 | void display(infix *t) | |
| 50 | {
| |
| 51 | int i; | |
| 52 | int n=(int)strlen(t->b); | |
| 53 | for(i=0;i<n;i++) | |
| 54 | {
| |
| 55 | - | printf("%d",t->b[i]);
|
| 55 | + | printf("%s",t->b[i]);
|
| 56 | } | |
| 57 | } | |
| 58 | ||
| 59 | ||
| 60 | void push(infix *t,char a) | |
| 61 | {
| |
| 62 | ||
| 63 | t->tos++; | |
| 64 | t->s[t->tos]=a; | |
| 65 | } | |
| 66 | ||
| 67 | void pop(infix *t,char k) | |
| 68 | {
| |
| 69 | if(k=='(')
| |
| 70 | {
| |
| 71 | t->tos--; | |
| 72 | } | |
| 73 | else | |
| 74 | {
| |
| 75 | transfer(t,k); | |
| 76 | t->tos--; | |
| 77 | } | |
| 78 | } | |
| 79 | ||
| 80 | int isoperand(char a) | |
| 81 | {
| |
| 82 | if(a=='+'||a=='-'||a=='%'||a=='/'||a=='*'||a=='(')
| |
| 83 | return 1; | |
| 84 | else | |
| 85 | return 0; | |
| 86 | } | |
| 87 | ||
| 88 | ||
| 89 | ||
| 90 | void convert(infix *t) | |
| 91 | {
| |
| 92 | int i; | |
| 93 | int n=(int)strlen(t->a); | |
| 94 | for(i=0;i<n;i++) | |
| 95 | {
| |
| 96 | if(isoperand(t->a[i])) | |
| 97 | {
| |
| 98 | if (isempty(t)) | |
| 99 | {
| |
| 100 | push(t,t->a[i]); | |
| 101 | } | |
| 102 | else if(ipr(t->a[i])>rpr(t->s[t->tos])) | |
| 103 | {
| |
| 104 | push(t,t->a[i]); | |
| 105 | } | |
| 106 | else if(ipr(t->a[i])<rpr(t->s[t->tos])) | |
| 107 | {
| |
| 108 | while(isempty(t)!=1||ipr(t->a[i])>rpr(t->s[t->tos])) | |
| 109 | {
| |
| 110 | pop(t,t->a[i]); | |
| 111 | } | |
| 112 | push(t,t->a[i]); | |
| 113 | } | |
| 114 | else if(t->a[i]==')') | |
| 115 | {
| |
| 116 | while(t->s[t->tos]!='(')
| |
| 117 | {
| |
| 118 | pop(t,t->a[i]); | |
| 119 | } | |
| 120 | ||
| 121 | } | |
| 122 | else | |
| 123 | {
| |
| 124 | transfer(t,t->a[i]); | |
| 125 | } | |
| 126 | ||
| 127 | } | |
| 128 | } | |
| 129 | } | |
| 130 | ||
| 131 | void main() | |
| 132 | {
| |
| 133 | ||
| 134 | infix s; | |
| 135 | s.postindex=0; | |
| 136 | s.tos=-1; | |
| 137 | printf("Enter the infix expression\n");
| |
| 138 | gets(s.a); | |
| 139 | convert(&s); | |
| 140 | printf("\nThe Postfix expression is \n");
| |
| 141 | display(&s); | |
| 142 | getchar(); | |
| 143 | } |
