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  1. #include<stdio.h>
  2. #include<stdlib.h>
  3. #include<ctype.h>
  4. #include<math.h>
  5. #include<string.h>
  6.  
  7. //*in - input array
  8. //* postfix - array for psuedo postfix expression
  9. //* valArr - array for stoaring values in expression
  10. char in[200],postfix[200], opSt[50];
  11. float valArr[50],evalSt[20];
  12. int opTop =-1,vTop =-1,eTop=-1;
  13.  
  14.  
  15.  
  16.  
  17. char pushOp(char c){
  18.     if(opTop <199){
  19.         opTop++;
  20.         opSt[opTop] = c;
  21.         return opSt[opTop];
  22.     }else{
  23.         printf("opStack Overflow Error!!!\n");
  24.         return 0;
  25.     }
  26. }
  27. float pushVal(float val){
  28.     if(vTop <49){
  29.         vTop++;
  30.         valArr[vTop] =val;
  31.         return valArr[vTop];
  32.     }else{
  33.         printf("valArrack Overflow Error!!!\n");
  34.         return 0;
  35.     }
  36. }
  37. float pushEval(float val){
  38.     if(eTop <19){
  39.         eTop++;
  40.         evalSt[eTop] =val;
  41.         return evalSt[eTop];
  42.     }else{
  43.         printf("evalArrack Overflow Error!!!\n");
  44.         return 0;
  45.     }
  46. }
  47.  
  48. char popOp(){
  49.  
  50.     if(opTop !=-1){
  51.         char val = opSt[opTop];
  52.         opTop--;
  53.         return val;
  54.     }else{
  55.         printf("opStack Empty Error!!!\n");
  56.         return 0;
  57.     }
  58.  
  59. }
  60.  
  61. float popVal(){
  62.  
  63.     if(vTop !=-1){
  64.         float val = valArr[vTop];
  65.         vTop--;
  66.         return val;
  67.     }else{
  68.         printf("valArr Empty Error!!!\n");
  69.         return 0;
  70.     }
  71.  
  72. }
  73. float popEval(){
  74.  
  75.     if(eTop !=-1){
  76.         float val = evalSt[eTop];
  77.         eTop--;
  78.         return val;
  79.     }else{
  80.         printf("evalStack Empty Error!!!\n");
  81.         return 0;
  82.     }
  83.  
  84. }
  85.  
  86.  
  87.  
  88.  
  89. //* Actual Infix Array
  90. char infix[250];
  91.  
  92. //* prepares the input array for converting to postifx array
  93. void prepParse(){
  94.  
  95.     char pre;
  96.     int i =0,j=0;
  97.     if(in[i]=='-'){
  98.         infix[j++] = '(';
  99.         infix[j++] = '0';
  100.         infix[j++] = '-';
  101.         infix[j++] = in[++i];
  102.         infix[j++] = ')';
  103.         i++;
  104.     }
  105.     while(in[i]!='\0'){
  106.         if(isdigit(in[i])||in[i] =='.'){
  107.             infix[j] = in[i];
  108.             i++;
  109.             j++;
  110.             pre = in[i];
  111.         }else if(in[i] == '*' && in[i+1] == '*'){
  112.             infix[j] = 'E';
  113.             j++;i+=2;
  114.             pre = in[i];
  115.         }else if(in[i] == '-' && (pre == '+'||pre == '-'||pre == '*'||pre == '/'||pre == '%'||pre == 'e'||pre == 'E')){
  116.             infix[j++] = '(';
  117.             infix[j++] = '0';
  118.             infix[j++] = '-';
  119.             infix[j++] = in[++i];
  120.             infix[j++] = ')';
  121.             i++;
  122.         }else{
  123.             infix[j] = in[i];
  124.             j++;i++;
  125.         }
  126.  
  127.  
  128.     }
  129.  
  130.  
  131.  
  132. }
  133.  
  134. //* converts numbers in in array to float number
  135. float parseVal(int k){
  136.     int dec =0;
  137.     float val = 0.0;
  138.     while(isdigit(infix[k])){
  139.         val = val*10 + (float)(infix[k]-'0');
  140.         k++;
  141.     }
  142.  
  143.     if(infix[k] == '.'){
  144.          k++;
  145.     while(isdigit(infix[k])){
  146.         val = val*10 + (float)(infix[k]-'0');
  147.         k++;
  148.         dec++;
  149.     }}
  150.     val = nextafterf(val/pow(10,dec),val+1);
  151.     pushVal(val);
  152.     return k;
  153. }
  154.  
  155.  
  156. int priority(char c){
  157.     if(c == 'e' || c =='E'){
  158.         return 4;
  159.     }else if(c =='*'||c=='/'||c == '%'){
  160.         return 3;
  161.     }else if(c =='+'||c =='-'){
  162.         return 2;
  163.     }else {
  164.         return 1;
  165.     }
  166. }
  167.  
  168.  
  169.  
  170. //* convers infix operation to psuedo operation
  171. void convert(){
  172.  
  173.     int i =0,j=0,len=0;
  174.     float val =0.0;
  175.     char x,t;
  176.     x = infix[0];
  177.     while(x!='\0'){
  178.  
  179.         if(isdigit(x)){
  180.             i = parseVal(i)-1;
  181.             postfix[j] = 'a';
  182.             j++;    
  183.         }else if(x =='('){
  184.             pushOp(x);
  185.         }else if(x==')'){
  186.             t=popOp();
  187.  
  188.             while(t != '('){
  189.  
  190.                 postfix[j] = t;
  191.                 j++;
  192.                 t = popOp();
  193.             }
  194.         }else if(x == '+'||x == '-'||x == '*'||x == '/'||x == '%'||x == 'e'||x == 'E'){
  195.             if(opTop ==-1||priority(x)>priority(opSt[opTop])){
  196.                 pushOp(x);
  197.             }else{
  198.                 while(opTop!=-1 && priority(x)<=priority(opSt[opTop])){
  199.                     t = popOp();
  200.                     postfix[j] = t;
  201.                     j++;
  202.                 }
  203.  
  204.                 pushOp(x);
  205.             }
  206.         }
  207.         i++;
  208.         x = infix[i];
  209.  
  210.  
  211.  
  212.     }
  213.  
  214.      while(opTop!= -1){
  215.         t = popOp();
  216.         postfix[j] = t;
  217.         j++;
  218.     }
  219. }
  220.  
  221. void eval(){
  222.     int temp =0,i=0;
  223.     char op;
  224.     float t =0.0,op1,op2;
  225.     while(temp <vTop/2 +1){
  226.         t = valArr[temp];
  227.         valArr[temp] = valArr[vTop-temp];
  228.          valArr[vTop-temp] = t;
  229.          temp++;
  230.     }
  231.     op = postfix[i];
  232.     while( op != '\0'){
  233.         if(postfix[i] == 'a'){
  234.             pushEval(popVal());
  235.         }else{
  236.             op2 = popEval();
  237.             op1 = popEval();
  238.             switch(op){
  239.                 case '+':{ pushEval(op1+op2);break;}
  240.                 case '-':{pushEval(op1-op2);break;}
  241.                 case '*':{pushEval(op1*op2);break;}
  242.                 case '/':{pushEval(op1/op2);break;}
  243.                 case '%':{pushEval((int)op1%(int)op2);break;}
  244.                 case 'e':
  245.                 case 'E' : {pushEval(pow(op1,op2));break;}
  246.             }
  247.         }
  248.         op = postfix[++i];
  249.     }
  250.  
  251.  
  252. }
  253. void main(){
  254.  
  255.     float val;
  256.     printf("Give the expression\n");
  257.     scanf("%s",in);
  258.     prepParse();
  259.     convert();
  260.     eval();
  261.     val = popEval();
  262.     printf("Answer is %f \n",nexttoward(val,val+1));
  263. }
Runtime error #stdin #stdout 0s 4544KB
comments (?)
stdin
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(4+8)*(6-5)/((3-2)*(2+5))
stdout
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Give the expression
Answer is -0.214286
https://ideone.com/4Z0EBV
language:
C (gcc 8.3)
created:
4 years ago
visibility:
public

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