mirror of https://github.com/TheAlgorithms/C
parent
6974f28d61
commit
f361d45483
31
convert.c
31
convert.c
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@ -1,18 +1,22 @@
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#include<stdio.h>
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char stack[20];
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int top = -1;
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void push(char x)
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//convert infix to postfix
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#include <stdio.h>
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char stack[20]; //declaring an empty stack
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int top = -1; //declaring top of stack
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void push(char x) //push function
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{
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stack[++top] = x;
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stack[++top] = x; //each time it is pushed top is increamented
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}
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char pop()
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char pop() //pop function
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{
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if(top == -1)
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return -1;
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else
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return stack[top--];
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return stack[top--]; //each time it is popped top is decreamented
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}
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int priority(char x)
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int priority(char x) // to check the priority of characters
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{
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if(x == '(')
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return 0;
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@ -35,23 +39,24 @@ int main()
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{
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if(isalnum(*e))
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printf("%c",*e);
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else if(*e == '(')
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else if(*e == '(') //push it directly into the stack
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push(*e);
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else if(*e == ')')
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else if(*e == ')') //pop until we gwt the left parenthesis
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{
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while((x = pop()) != '(')
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printf("%c", x);
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}
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else
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{
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while(priority(stack[top]) >= priority(*e))
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while(priority(stack[top]) >= priority(*e)) //pop until priority of top of stack is greater than equal to priority of expressions character
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printf("%c",pop());
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push(*e);
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push(*e); //otherwise push
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}
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e++;
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}
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// keep popping until top is not -1
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while(top != -1)
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{
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printf("%c",pop());
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printf("%c",pop());
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}
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}
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