leetcode/src/validNumber/validNumber.cpp at master · ourstart/leetcode · GitHub

History

118 lines (103 loc) · 2.53 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

// Source : https://oj.leetcode.com/problems/valid-number/

// Author : Hao Chen

// Date : 2014-08-26

/**********************************************************************************

* Validate if a given string is numeric.

* Some examples:

* "0" => true

* " 0.1 " => true

* "abc" => false

* "1 a" => false

* "2e10" => true

* Note: It is intended for the problem statement to be ambiguous.

* You should gather all requirements up front before implementing one.

**********************************************************************************/

#include <iostream>

using namespace std;

bool isdigit(const char c){

return (c>='0' && c<='9');

}

bool isspace(const char c) {

return (c==' ' || c =='\t' || c=='\n' || c=='\r' || c=='\f' || c=='\v');

}

bool isNumber(const char *s) {

bool point = false;

bool hasE = false;

//trim the space

while(isspace(*s)) s++;

//check empty

if (*s == '\0' ) return false;

//check sign

if (*s=='+' || *s=='-') s++;

const char *head = s;

for(; *s!='\0'; s++){

// if meet point

if ( *s == '.' ){

if ( hasE == true || point == true){

return false;

}

if ( s == head && !isdigit(*(s+1)) ){

return false;

}

point = true;

continue;

}

//if meet "e"

if ( *s == 'e' ){

if ( hasE == true || s == head) {

return false;

}

s++;

if ( *s=='+' || *s=='-' ) s++;

if ( !isdigit(*s) ) return false;

hasE = true;

continue;

}

//if meet space, check the rest chars are space or not

if (isspace(*s)){

for (; *s != '\0'; s++){

if (!isspace(*s)) return false;

}

return true;

}

if ( !isdigit(*s) ) {

return false;

}

return true;

}

#define TEST(s) cout << "\"" << s << "\"" << " : " << isNumber(s) << endl

int main(int argc, char** argv)

{

const char* s="123";

if(argc>1){

s = argv[1];

}

TEST(s);

TEST("1.044");

TEST(" 1.044 ");

TEST("1.a");

TEST("abc");

TEST("e");

TEST("1e");

TEST("1e2");

TEST("");

TEST(" ");

TEST("1.");

TEST(".2");

TEST(" . ");

TEST(".");

TEST("1.2.3");

TEST("1e2e3");

TEST("1..");

TEST("+1.");

TEST(" -1.");

TEST("6e6.5");

TEST("005047e+6");

return 0;

}

leetcode/src/validNumber/validNumber.cpp at master · ourstart/leetcode · GitHub

Expand file tree

Breadcrumbs

validNumber.cpp

Latest commit

History

Breadcrumbs

validNumber.cpp

File metadata and controls